SEVENTH FRAMEWORK PROGRAMME Capacities Specific Programme Research Infrastructures Project No.: 227887 SERIES SEISMIC ENGINEERING RESEARCH INFRASTRUCTURES FOR EUROPEAN SYNERGIES Workpackage [WP10/TA6 – IFSTTAR Centrifuge] DRESBUS II Investigation of the Seismic Behaviour of Shallow Rectangular Underground Structures in Soft Soils Using Centrifuge Experiments User Group Leader: Dr. E. Rovithis Revision: Final May, 2013
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SERIES DRESBUS II Final Report · a low pass filter – EQ4..... 45 Fig. 4.21 Walls deformations obtained using a band pass filter – EQ4..... 46 Fig. 4.22 Walls maximum deformations
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SEVENTH FRAMEWORK PROGRAMME Capacities Specific Programme
Research Infrastructures
Project No.: 227887
SERIES SEISMIC ENGINEERING RESEARCH INFRASTRUCTURES FOR
EUROPEAN SYNERGIES
Workpackage [WP10/TA6 – IFSTTAR Centrifuge]
DRESBUS II Investigation of the Seismic Behaviour of Shallow Rectangular
Underground Structures in Soft Soils Using Centrifuge Experiments
User Group Leader: Dr. E. Rovithis Revision: Final
May, 2013
SERIES 227887 TA Project: DRESBUS II
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ABSTRACT
This report contains centrifuge recordings and data interpretation as the outcome of the
Transnational Access project DRESBUS II “Investigation of the seismic behavior of shallow
rectangular underground structures in soft soils using centrifuge experiments” that was
performed under SERIES Research Program. DRESBUS II was designed, compiled and
completed on December 2012, as a collaborative project between the Institut Français des
Sciences et Technologie des Transports, de l'Amménagement et des Réseaux, France (IFSTTAR)
(acting as the Access Provider), the Earthquake Planning and Protection Organization, Greece
(EPPO-ITSAK) and the Laboratory of Soil Mechanics, Foundations and Geotechnical
Earthquake Engineering of Aristotle University of Thessaloniki, Greece (AUTH), both of them
acting as the main Transnational Access Users.
Seven centrifuge test sequences were carried out in total referring to flexible or rigid tunnel
sections, smooth or rough soil-tunnel interface (smoothed aluminium surface and grooved
aluminium with depth equivalent to sand D50) and dry or saturated Fontainebleau sand N34 with
ID = 70%. Novel techniques for the sand pluvation, models saturation and waterproofing of the
tunnel sections were used during centrifuge tests set-up. Each soil-tunnel system was excited by
the same input sequence: a real recording from Northridge earthquake scaled to three levels of
peak acceleration (0.1g, 0.2g and 0.3g) followed by a sine wave at 0.3g. A dense monitoring
scheme was employed to record soil-tunnel response comprising of miniature piezoelectric
accelerometers within the soil or attached to the tunnel section and the ESB container,
displacement sensors to record the surface ground settlement and pore pressure sensors to
measure pore pressure dissipation, for the saturated cases. Furthermore, specially designed
extensometers were used to record the racking deformations of the tunnel section and diagonal
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“blade” extensometers were installed along the longitudinal axis of the tunnel to verify the
homogeneity of deformation and control out of plane response of the structure.
Experimental recordings obtained from each test are reported herein in detail followed by a
preliminary interpretation of the experimental data. Seismic response of the tunnel sections is
commented as affected by the model parameters under investigation. In this regard, the acquired
datasets offer valuable experimental evidence on fundamental aspects of seismic behaviour of
soil-tunnel systems, providing a well-documented basis for validating numerical models and
design methods that are commonly employed in practice.
Fig. 1.1 Daikai Station. (a) Settlements of the overlaying roadway caused by the subway collapse, (b) Collapse of the central columns of the station (Special Issue of Soil and Foundations, 1996) ......................................................................................................................... 2 Fig.2.1 (a) Geotechnical Centrifuge at IFSTTAR, (b) Earthquake Actidyn QS 80 actuator, (c) ESB container ................................................................................................................................. 3 Fig. 2.2 Tunnels sections ................................................................................................................ 5 Fig. 2.3 Definition of roughness ..................................................................................................... 6 Fig. 2.4 Relation between the sand grain size and the grooves dimensions ................................... 6 Fig. 2.5 Device for the deformation tests of the tunnel specimens................................................. 7 Fig. 2.6 Small strain shear wave velocity profiles according to Hardin and Drenvich model ....... 8 Fig. 2.7 Model preparation.............................................................................................................. 9 Fig. 2.8 Installation of the waterproof rubber membrane on the ESB container .......................... 11 Fig. 2.9 Schematic representation of the saturation system setup ................................................ 12 Fig. 2.10 Saturation system setup ................................................................................................. 12 Fig. 2.11 Typical connection of the tunnel with the ESB box for the dry sand tests.................... 13 Fig. 2.12 Details of the tunnels – ESB box connections (a) Dry sand tests, (b) Saturated sand tests; first solution, (c) Saturated sand tests; final solution........................................................... 13 Fig. 2.13 Typical model layout for a dry test................................................................................ 15 Fig. 2.14 Typical model layout for a saturated test....................................................................... 16 Fig. 2.15 “Fork” system extensometer.......................................................................................... 18 Fig. 2.16 Design sheet of the fork extensometers......................................................................... 19 Fig. 2.17 Calibration device for the fork extensometers - Representative calibration curves of a fork system.................................................................................................................................... 20 Fig. 2.18 Diagonal extensometers................................................................................................. 20 Fig. 2.19 Design sheet for the diagonal extensometers ................................................................ 21 Fig. 2.20 Calibration device for the diagonal extensometers........................................................ 21 Fig. 2.21 Shaking table base configuration................................................................................... 23 Fig. 2.22 Relative position of the CPT with respect to the tunnel (top view) .............................. 23 Fig. 2.23 Nominal input motions .................................................................................................. 24 Fig. 4.1 Test DRESBUS_2_1_1 model set up and instrumentation scheme ................................ 28 Fig. 4.2 Accelerometers vertical arrays ........................................................................................ 30 Fig. 4.3 Processed acceleration time histories – EQ1................................................................... 33 Fig. 4.4 Processed acceleration time histories – EQ2................................................................... 34 Fig. 4.5 Processed acceleration time histories – EQ3................................................................... 35 Fig. 4.6 Processed acceleration time histories – EQ4................................................................... 36
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Fig. 4.7 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ1......................................................................................................... 37 Fig. 4.8 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ2......................................................................................................... 37 Fig. 4.9 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ3......................................................................................................... 38 Fig. 4.10 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ4......................................................................................................... 38 Fig. 4.11 Typical transfer functions along vertical accelerometers arrays – EQ1........................ 39 Fig. 4.12 Vertical accelerations – EQ2 ......................................................................................... 39 Fig. 4.13 Stress-strain loops – EQ1 .............................................................................................. 40 Fig. 4.14 Stress-strain loops – EQ4 .............................................................................................. 40 Fig. 4.15 Shear wave velocity profiles computed along vertical accelerometers arrays; comparison with Vso computed according to Hardin and Drenvich (1972) formulation.............. 41 Fig. 4.16 Walls deformations obtained using a low pass filter – EQ1.......................................... 42 Fig. 4.17 Walls deformations obtained using a low pass filter – EQ4.......................................... 43 Fig. 4.18 Walls maximum deformations obtained using a low pass filter.................................... 44 Fig. 4.19 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a low pass filter – EQ1.................................................................................................................. 45 Fig. 4.20 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a low pass filter – EQ4.................................................................................................................. 45 Fig. 4.21 Walls deformations obtained using a band pass filter – EQ4........................................ 46 Fig. 4.22 Walls maximum deformations obtained using a band pass filter.................................. 47 Fig. 4.23 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a band pass filter – EQ3................................................................................................................ 48 Fig. 4.24 CPT test results.............................................................................................................. 48 Fig. 4.25 Soil surface settlements ................................................................................................. 49 Fig. 4.26 Test DRESBUS_2_2_1 model set up and instrumentation scheme.............................. 50 Fig. 4.27 Processed acceleration time histories – EQ1................................................................. 53 Fig. 4.28 Processed acceleration time histories – EQ2................................................................. 54 Fig. 4.29 Processed acceleration time histories – EQ3................................................................. 55 Fig. 4.30 Processed acceleration time histories – EQ4................................................................. 56 Fig. 4.31 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ1......................................................................................................... 57 Fig. 4.32 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ2......................................................................................................... 57 Fig. 4.33 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. – EQ3................................................................................................................ 58 Fig. 4.34 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ4......................................................................................................... 58 Fig. 4.35 Shear wave velocity profiles computed along vertical accelerometers arrays; comparison with Vso computed according to Hardin and Drenvich (1972) formulation.............. 59 Fig. 4.36 Walls deformations obtained using a low pass filter – EQ2.......................................... 60 Fig. 4.37 Walls maximum deformations obtained using a low pass filter.................................... 61 Fig. 4.38 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a low pass filter – EQ3.................................................................................................................. 62 Fig. 4.39 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a band pass filter – EQ4................................................................................................................ 62
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Fig. 4.40 Walls maximum deformations obtained using a band pass filter.................................. 63 Fig. 4.41 CPT test results.............................................................................................................. 64 Fig. 4.42 Soil surface settlements ................................................................................................. 64 Fig. 4.43 Test DRESBUS_2_3_1 model set up and instrumentation scheme.............................. 65 Fig. 4.44 Processed acceleration time histories – EQ1................................................................. 68 Fig. 4.45 Processed acceleration time histories – EQ2................................................................. 69 Fig. 4.46 Processed acceleration time histories – EQ3................................................................. 70 Fig. 4.47 Processed acceleration time histories – EQ4................................................................. 71 Fig. 4.48 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ1......................................................................................................... 72 Fig. 4.49 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ2......................................................................................................... 72 Fig. 4.50 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ3......................................................................................................... 73 Fig. 4.51 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ4......................................................................................................... 73 Fig. 4.52 Shear wave velocity profiles computed along vertical accelerometers arrays; comparison with Vso computed according to Hardin and Drenvich (1972) formulation ............ 74 Fig. 4.53 Walls deformations obtained using a low pass filter – EQ1.......................................... 75 Fig. 4.54 Walls deformations obtained using a low pass filter – EQ4.......................................... 76 Fig. 4.55 Walls maximum deformations obtained using a low pass filter.................................... 77 Fig. 4.56 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a low pass filter – EQ2.................................................................................................................. 78 Fig. 4.57 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a band pass filter – EQ4................................................................................................................ 78 Fig. 4.58 Walls maximum deformations obtained using a band pass filter.................................. 79 Fig. 4.59 CPT test results.............................................................................................................. 80 Fig. 4.60 Soil surface settlements ................................................................................................. 80 Fig. 4.61 Test DRESBUS_2_4_2 model set up and instrumentation scheme.............................. 81 Fig. 4.62 Processed acceleration time histories – EQ1................................................................. 85 Fig. 4.63 Processed acceleration time histories – EQ2................................................................. 86 Fig. 4.64 Processed acceleration time histories – EQ3................................................................. 87 Fig. 4.65 Processed acceleration time histories – EQ4................................................................. 88 Fig. 4.66 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ1......................................................................................................... 89 Fig. 4.67 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ2......................................................................................................... 89 Fig. 4.68 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ3......................................................................................................... 90 Fig. 4.69 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ4......................................................................................................... 90 Fig. 4.70 Walls deformations obtained using a low pass filter – EQ2.......................................... 91 Fig. 4.71 Walls deformations obtained using a low pass filter – EQ4.......................................... 92 Fig. 4.72 Walls maximum deformations obtained using a low pass filter.................................... 93 Fig. 4.73 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a low pass filter – EQ1.................................................................................................................. 94 Fig. 4.74 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a band pass filter – EQ1................................................................................................................ 94
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Fig. 4.75 Walls maximum deformations recorded by fork extensometers; low pass filter .......... 95 Fig. 4.76 Water pore pressures during and after shaking – EQ1 .................................................. 96 Fig. 4.77 Water pore pressures during and after shaking – EQ2 .................................................. 96 Fig. 4.78 Water pore pressures during and after shaking – EQ3 .................................................. 97 Fig. 4.79 Water pore pressures during and after shaking – EQ4 .................................................. 97 Fig. 4.80 CPT test results.............................................................................................................. 98 Fig. 4.81 Test DRESBUS_2_5_1 model set up and instrumentation scheme.............................. 99 Fig. 4.82 Processed acceleration time histories – EQ1............................................................... 102 Fig. 4.83 Processed acceleration time histories – EQ2............................................................... 103 Fig. 4.84 Processed acceleration time histories – EQ3............................................................... 104 Fig. 4.85 Processed acceleration time histories – EQ4............................................................... 105 Fig. 4.86 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ1....................................................................................................... 106 Fig. 4.87 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ2....................................................................................................... 106 Fig. 4.88 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ3....................................................................................................... 107 Fig. 4.89 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ4....................................................................................................... 107 Fig. 4.90 Walls deformations obtained using a low pass filter – EQ1........................................ 108 Fig. 4.91 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a low pass filter – EQ1................................................................................................................ 109 Fig. 4.92 Walls maximum deformations obtained using a low pass filter.................................. 110 Fig. 4.93 Walls maximum deformations obtained using a band pass filter................................ 111 Fig. 4.94 CPT test results............................................................................................................ 112 Fig. 4.95 Soil surface settlements ............................................................................................... 112 Fig. 4.96 Test DRESBUS_2_6_1 model set up and instrumentation scheme............................ 113 Fig. 4.97 Maximum Processed acceleration time histories – EQ1 ............................................. 116 Fig. 4.98 Processed acceleration time histories – EQ2............................................................... 117 Fig. 4.99 Processed acceleration time histories – EQ3............................................................... 118 Fig. 4.100 Processed acceleration time histories – EQ4............................................................. 119 Fig. 4.101 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ1....................................................................................................... 120 Fig. 4.102 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ2....................................................................................................... 120 Fig. 4.103 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ3....................................................................................................... 121 Fig. 4.104 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ4....................................................................................................... 121 Fig. 4.105 Walls deformations obtained using a low pass filter – EQ1...................................... 122 Fig. 4.106 Walls maximum deformations obtained using a low pass filter................................ 123 Fig. 4.107 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a low pass filter – EQ1................................................................................................................ 124 Fig. 4.108 Walls maximum deformations obtained using a band pass filter.............................. 125 Fig. 4.109 Water pore pressures during and after shaking – EQ1 .............................................. 126 Fig. 4.110 Water pore pressures during and after shaking – EQ2 .............................................. 126 Fig. 4.111 Water pore pressures during and after shaking – EQ3 .............................................. 127 Fig. 4.112 Water pore pressures during and after shaking – EQ4 .............................................. 127
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Fig. 4.113 Soil surface settlements ............................................................................................. 128 Fig. 4.114 Test DRESBUS_2_7_1 model set up and instrumentation scheme.......................... 129 Fig. 4.115 Processed acceleration time histories – EQ1............................................................. 132 Fig. 4.116 Processed acceleration time histories – EQ2............................................................. 133 Fig. 4.117 Processed acceleration time histories – EQ3............................................................. 134 Fig. 4.118 Processed acceleration time histories – EQ4............................................................. 135 Fig. 4.119 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ1....................................................................................................... 136 Fig. 4.120 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ2....................................................................................................... 136 Fig. 4.121 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ3....................................................................................................... 137 Fig. 4.122 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ4....................................................................................................... 137 Fig. 4.123 Walls deformations obtained using a low pass filter – EQ1...................................... 138 Fig. 4.124 Walls maximum deformations obtained using a low pass filter................................ 139 Fig. 4.125 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a low pass filter – EQ1................................................................................................................ 140 Fig. 4.126 Walls maximum deformations obtained using a band pass filter.............................. 141 Fig. 4.127 Water pore pressures during and after shaking – EQ1 .............................................. 141 Fig. 4.128 Water pore pressures during and after shaking – EQ2 .............................................. 142 Fig. 4.129 Water pore pressures during and after shaking – EQ3 .............................................. 142 Fig. 4.130 Water pore pressures during and after shaking – EQ4 .............................................. 143 Fig. 4.131 Soil surface settlements during swing up .................................................................. 143 Fig. 4.132 Soil surface settlements during shaking .................................................................... 144 Fig. 5.1 CPT test results for the dry sand tests............................................................................ 145 Fig. 5.2 Maximum horizontal acceleration at the soil free field (Array 2) for the dry tests....... 146 Fig. 5.3 Maximum horizontal acceleration at the soil free field (Array 2) for the saturated tests..................................................................................................................................................... 147 Fig. 5.4 Maximum racking deformations for different input motion amplitudes – rough flexible tunnel in dry sand (DRESBUS2_1_1) ........................................................................................ 148 Fig. 5.5 Maximum racking deformations for different input motion amplitudes – smooth flexible tunnel in dry sand (DRESBUS2_2_1) ........................................................................................ 148 Fig. 5.6 Maximum racking deformations for different input motion amplitudes – rough rigid tunnel in dry sand (DRESBUS2_3_1) ........................................................................................ 149 Fig. 5.7 Maximum racking deformations for different input motion amplitudes – rough rigid tunnel in saturated sand (DRESBUS2_4_2) ............................................................................... 149 Fig. 5.8 Maximum racking deformations for different input motion amplitudes – smooth rigid tunnel in dry sand (DRESBUS2_5_1) ........................................................................................ 150 Fig. 5.9 Maximum racking deformations for different input motion amplitudes – smooth rigid tunnel in saturated sand (DRESBUS2_6_1) ............................................................................... 150 Fig. 5.10 Maximum racking deformations for different input motion amplitudes – rough rigid tunnel in saturated sand (DRESBUS2_7_1) ............................................................................... 151 Fig. 5.11 Maximum racking deformations for different input motion amplitudes – rough vs. smooth flexible tunnel in dry sand (DRESBUS2_1_1 vs. DRESBUS2_2_1)............................ 152 Fig. 5.12 Maximum racking deformations for different input motion amplitudes – rough vs. smooth rigid tunnel in saturated sand (DRESBUS2_6_1 vs. DRESBUS2_7_1) ....................... 153
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Fig. 5.13 Maximum racking deformations for different input motion amplitudes – effect of sand saturation (DRESBUS2_3_1 vs. DRESBUS2_7_1)................................................................... 154
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List of Tables
Table 2.1 Scaling laws for geotechnical centrifuge tests (Schofield, 1980)................................... 4 Table 2.2 Fontainebleau sand NE 34 physical properties.............................................................. 4 Table 2.3 Mechanical properties of the aluminum alloy used ........................................................ 7 Table 2.4 Tunnels flexibility ratios based on Wang (1993) method............................................... 8 Table 2.5 Pouring parameters ....................................................................................................... 10 Table 2.6 Calibration parameters of the fork systems .................................................................. 18 Table 2.7 Calibration curves for the diagonal extensometers....................................................... 22 Table 2.8 DRESBUS II testing program....................................................................................... 22 Table 2.9 Extensometer systems used during each test ................................................................ 23 Table 2.10 Input motions characteristics (bracketed values: values in prototype scale) .............. 24 Table 4.1 Sensors numbering and exact positions ........................................................................ 29 Table 4.2 Extensometers numbering............................................................................................. 30 Table 4.3 Sensors numbering and exact positions ........................................................................ 51 Table 4.4 Extensometers numbering............................................................................................. 52 Table 4.5 Sensors numbering and exact positions ........................................................................ 66 Table 4.6 Extensometers numbering............................................................................................. 67 Table 4.7 Sensors numbering and exact positions ........................................................................ 82 Table 4.8 Extensometers numbering............................................................................................. 83 Table 4.9 Measured vs. theoretical water pore pressure at P1...................................................... 84 Table 4.10 Sensors numbering and exact positions .................................................................... 100 Table 4.11 Extensometers numbering......................................................................................... 101 Table 4.13 Sensors numbering and exact positions .................................................................... 114 Table 4.14 Extensometers numbering......................................................................................... 115 Table 4.12 Sensors numbering and exact positions .................................................................... 130 Table 4.13 Extensometers numbering......................................................................................... 131
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1 Introduction
Large underground structures such as tunnels and metro stations possess a vital socio-economic
role being a crucial part of the transportation and utility networks in an urban area. The
associated impact in case of earthquake induced damages denotes the paramount importance of a
safe seismic design, especially in seismically active areas.
Although recent earthquake events (Kobe 1995, Duzce 1999, Chi-Chi 1999 and Wenchuan 2008)
have demonstrated that underground structures may undergo extensive deformations or even
collapse (Sharma and Judd, 1991, Wang, 1993, Iida et al., 1996 among others), their seismic
response has been little explored compared to aboveground structures due to lack of
experimental data and well-documented field evidence (Cilingir and Madabhushi, 2011). In this
regard, design specifications for underground structures in modern seismic codes are based
primarily on simplified methods (Wang, 1993, Penzien, 2000, Hashash et al., 2001, ISO 23469,
2005, FWHA, 2009), the implementation of which may lead to a substantially different seismic
design for this type of structures (Pitilakis and Tsinidis, 2012).
A substantial contribution to the knowledge of seismic behavior of underground structures may
be accomplished by means of well-focused experimental data, allowing investigation of crucial
response parameters such as seismic earth pressures distribution on the side walls of the
structure, seismic shear stresses distribution around the perimeter of the structure and definition
of impedance functions to be implemented in simplified Winkler models for underground
structures.
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(a)
(b)
Fig. 1.1 Daikai Station. (a) Settlements of the overlaying roadway caused by the subway collapse, (b) Collapse of the central columns of the station (Special Issue of Soil and
Foundations, 1996)
The above research objectives motivated the realization of the collaborative experimental
Transnational Access project DRESBUS II “Investigation of the seismic behavior of shallow
rectangular underground structures in soft soils using centrifuge experiments” offered by the
SERIES research project. More specifically, DRESBUS II TA project dealt with the
investigation of shallow rectangular tunnels seismic response by means of dynamic centrifuge
testing. The experimental study was elaborated in the geotechnical centrifuge facility of
IFSTTAR under a centrifuge acceleration of 40g. Well-documented experimental data was
recorded for a wide set of soil-tunnel systems allowing a better understanding of the seismic
behavior of underground structures, as affected by salient parameters such as soil-structure
relative flexibility, soil-tunnel interface properties, soil saturation and amplitude of excitation.
Following a detailed description of DRESBUS II project set up, the herein report provides (a) a
representative set of experimental recordings obtained from each centrifuge test case and (b)
comparisons between selected soil-tunnel systems to highlight important aspects of the physical
problem within a preliminary interpretation of the recorded data.
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2 DRESBUS II experimental program
2.1 IFSTTAR CENTRIFUGE FACILITY
DREBSUS II TA project was hosted by the centrifuge facility of IFSTTAR in Nantes, France.
IFSTTAR centrifuge has a radius of 5.5m and a capacity of two tonnes under a centrifugal
acceleration of 100g. The dimensions of the swinging basket supporting the model are 1.4m ×
1.1m.
Earthquake input motions were applied at the base of the soil-tunnel model, using the specially
designed actuator Actidyn QS 80 (Chazelas et al., 2008) being able to impose both sinusoidal
and real record input motions up to 400kg of payload mass. It is designed to work under a
centrifugal acceleration up to 80g, while it can apply input motions of peak acceleration at 0.5g,
allowing modeling of a wide frequency range (30-300Hz for real earthquakes).
A large Equivalent Shear Box (ESB) was employed to mount the models, having inner
dimensions 800mm in length, 340mm in width and 409mm in depth. The box is designed to
match the shear stiffness of the contained soil for the range of shear strains of interest, in order to
minimize spurious boundary effects arising from soil-container interactions.
The accelerometers were installed in vertical arrays (Fig. 4.2). Figs. 4.3-4.6 show filtered
acceleration time histories. Figs. 4.7-4.10 summarize the distribution of the maximum horizontal
accelerations with depth indicating soil amplification effects.
A2A3
A4
A20
A12
A9 A6 A13A7
A10A11
A8 A5
A14A15
Array 1
Array 2
Array 3
Array 4
Array 5
A16
A17
A18A19
A1
Fig. 4.2 Accelerometers vertical arrays
Fig. 4.11 presents representative transfer functions computed along the free field, the tunnel and
the reference array (ESB container) for EQ1. The results do not clearly show the predominant
frequencies of the soil-tunnel system.
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Fig. 4.12 presents vertical acceleration time histories near the soil base and on the tunnel’s roof
slab sides during EQ2 (control points 25 and 26 in Fig. 4.1), indicating a yawing movement of
the ESB container. The in-phase response of the tunnel roof corners denotes a racking-type of
deformation. However, further investigation is needed to comment on a possible mobilization of
a “rocking-motion component”.
Typical stress-strain loops based on Zeghal and Elgamal procedure (Zeghal and Elgamal, 1994)
between sets of accelerometers are presented in Figs. 4.13-4.14. In Fig. 4.15 the shear wave
velocities, estimated according to the mobilized shear moduli, derived from the stress-strain
loops, are compared to the small strain shear wave velocity (Vso). The latter is estimated
according to the Hardin and Drenvich (1976) model. The results indicate reduction of the
velocities with increasing amplitude of the input motion. Moreover, Vs seem to be lower close to
the tunnel section compared to free-field values.
Figs. 4.16-4.17 present filtered deformation time histories recorded on the tunnels wall. In the
third column the recorded at each level signals are compared, inverting the polarity of one of the
compared signals. The results referring to EQ1 and EQ4, indicate an out of phase response for
the sensors located at the same level, while similar results are reported for the other shakes. As
expected the walls deformations are increased towards the roof slab. The maximum wall
deformations, as recorded for both the walls are compared for all the shakes in Fig. 4.18. The
walls deformations are increased with the increase of the amplitude input motion. Moreover, the
results indicated minor differences between the walls distributions, revealing an almost
symmetric response of the walls.
Figs. 4.19-4.20 present typical time histories of the tunnel diagonal deformations recorded by the
diagonal blades, indicating an in plane response of the tunnels.
Similar results were reported using the band pass filter for the tunnel deformation signals (Figs.
4.21 - 4.23). The maximum walls deformations were slightly smaller than the values observed by
the low pass filter results, due to the preclusion of the small residual values in this case.
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CPT tests results obtained before and after the main test are summarized in Fig. 4.24. The results
indicate soil densification during shaking, as reflected in Fig. 4.25.
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0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A1 − Input
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A2
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A3
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A4
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A5
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A6
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A7
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A8
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A9
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A10
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A11
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A12
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A13
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A14
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A15
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A16
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A17
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A18
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A19
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A20
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A21
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A22
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A23
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A24
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A/4
0g
A25
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A26
Fig. 4.3 Processed acceleration time histories – EQ1
SERIES 227887 TA Project: DRESBUS II
34
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A1 − Input
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A2
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A3
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A4
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A5
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A6
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A7
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A8
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A9
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A10
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A11
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A12
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A13
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A14
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A15
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A16
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A17
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A18
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A19
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A20
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A21
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A22
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A23
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A24
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A/4
0g
A25
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A26
Fig. 4.4 Processed acceleration time histories – EQ2
SERIES 227887 TA Project: DRESBUS II
35
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A/4
0g
A1 − Input
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A2
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A3
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A4
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A5
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A6
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A/4
0g
A7
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A8
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A9
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A10
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A11
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A12
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A/4
0g
A13
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A14
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A15
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A16
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A17
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A18
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A/4
0g
A19
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A20
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A21
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A22
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A23
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A24
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A/4
0g
A25
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A26
Fig. 4.5 Processed acceleration time histories – EQ3
SERIES 227887 TA Project: DRESBUS II
36
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A/4
0g
A1 − Input
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A2
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A3
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A4
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A5
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A6
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A/4
0g
A7
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A8
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A9
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A10
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A11
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A12
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A/4
0g
A13
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A14
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A15
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A16
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A17
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A18
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A/4
0g
A19
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
A20
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
t(s)
A21
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
t(s)
A22
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
t(s)
A23
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
t(s)
A24
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
t(s)
A/4
0g
A25
0 0.16 0.32 0.48 0.64−0.6−0.3
00.30.6
t(s)
A26
Fig. 4.6 Processed acceleration time histories – EQ4
SERIES 227887 TA Project: DRESBUS II
37
0 0.07 0.14 0.21 0.280
0.09
0.18
0.27
0.36
Dep
th(m
)Array 1 − A/40g
0 0.07 0.14 0.21 0.280
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.07 0.14 0.21 0.28
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.07 0.14 0.21 0.28
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.07 0.14 0.21 0.280
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.1 0.15 0.2 0.250.05
0.06
0.07
0.08
0.09
0.1D
epth
(m)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.7 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ1
0 0.1 0.2 0.3 0.40
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 1 − A/40g0 0.1 0.2 0.3 0.4
0
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.1 0.2 0.3 0.4
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.1 0.2 0.3 0.4
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.1 0.2 0.3 0.40
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.2 0.25 0.3 0.35 0.40.05
0.06
0.07
0.08
0.09
0.1
Dep
th(m
)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.8 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ2
SERIES 227887 TA Project: DRESBUS II
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0 0.15 0.3 0.45 0.60
0.09
0.18
0.27
0.36
Dep
th(m
)Array 1 − A/40g
0 0.15 0.3 0.45 0.60
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.15 0.3 0.45 0.6
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.15 0.3 0.45 0.6
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.15 0.3 0.45 0.60
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.25 0.3 0.35 0.4 0.45 0.50.05
0.06
0.07
0.08
0.09
0.1D
epth
(m)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.9 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ3
0 0.2 0.4 0.6 0.80
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 1 − A/40g0 0.2 0.4 0.6 0.8
0
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.2 0.4 0.6 0.8
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.2 0.4 0.6 0.8
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.2 0.4 0.6 0.80
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.4 0.45 0.5 0.55 0.60.05
0.06
0.07
0.08
0.09
0.1
Dep
th(m
)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.10 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ4
SERIES 227887 TA Project: DRESBUS II
39
0 50 100 150 200 250 300 350 4000
5
10
15
20
f(Hz)
Am
plit
ud
e
Transfer functions
Reference arrayFree Field arrayTunnel array
Fig. 4.11 Typical transfer functions along vertical accelerometers arrays – EQ1
0 0.25 0.5 0.75 1−0.1
−0.05
0
0.05
0.1
t(s)
A/4
0g
A20
0 0.25 0.5 0.75 1−0.1
−0.05
0
0.05
0.1
t(s)
A25
0 0.25 0.5 0.75 1−0.1
−0.05
0
0.05
0.1
t(s)
A26
0.2 0.4 0.6−0.1
−0.05
0
0.05
0.1
t(s)
A/4
0g
A25 vs A26
Fig. 4.12 Vertical accelerations – EQ2
SERIES 227887 TA Project: DRESBUS II
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−0.08 −0.04 0 0.04 0.08−20
−10
0
10
20
stre
ss (
kPa)
A12−A13
−0.08 −0.04 0 0.04 0.08−20
−10
0
10
20A13−A14
−0.08 −0.04 0 0.04 0.08−20
−10
0
10
20A14−A15
−0.08 −0.04 0 0.04 0.08−20
−10
0
10
20
strain (%)
A6−A7
−0.08 −0.04 0 0.04 0.08−20
−10
0
10
20
strain (%)
stre
ss (
kPa)
A7−A8
−0.08 −0.04 0 0.04 0.08−20
−10
0
10
20
strain (%)
A9−A10
−0.08 −0.04 0 0.04 0.08−20
−10
0
10
20
strain (%)
A10−A11
Fig. 4.13 Stress-strain loops – EQ1
−0.6 −0.3 0 0.3 0.6−60
−30
0
30
60
stre
ss (
kPa)
A12−A13
−0.6 −0.3 0 0.3 0.6−60
−30
0
30
60A13−A14
−0.6 −0.3 0 0.3 0.6−60
−30
0
30
60A14−A15
−0.6 −0.3 0 0.3 0.6−60
−30
0
30
60
strain (%)
A6−A7
−0.6 −0.3 0 0.3 0.6−60
−30
0
30
60
strain (%)
stre
ss (
kPa)
A7−A8
−0.6 −0.3 0 0.3 0.6−60
−30
0
30
60
strain (%)
A9−A10
−0.6 −0.3 0 0.3 0.6−60
−30
0
30
60
strain (%)
A10−A11
Fig. 4.14 Stress-strain loops – EQ4
SERIES 227887 TA Project: DRESBUS II
41
0 100 200 3000
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
Dep
th(m
)Vs(m/s)
Array 2Array 4Array 5Hardin & Drenvich, 1972
EQ1
0 100 200 3000
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
Dep
th(m
)
Vs(m/s)
Array 2Array 4Array 5Hardin & Drenvich, 1972
EQ2
0 100 200 3000
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
Dep
th(m
)
Vs(m/s)
Array 2Array 4Array 5Hardin & Drenvich, 1972
EQ3
0 100 200 3000
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
Dep
th(m
)
Vs(m/s)
Array 2Array 4Array 5Hardin & Drenvich, 1972
EQ4
Fig. 4.15 Shear wave velocity profiles computed along vertical accelerometers arrays; comparison with Vso computed according to Hardin and Drenvich (1972) formulation
SERIES 227887 TA Project: DRESBUS II
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0 0.25 0.5 0.75 1−0.05
−0.025
0
0.025
0.05
D(m
m)
F1
0 0.25 0.5 0.75 1−0.05
−0.025
0
0.025
0.05F6
0.25 0.3 0.35−0.05
−0.025
0
0.025
0.05F1−F6
0 0.25 0.5 0.75 1−0.05
−0.025
0
0.025
0.05
D(m
m)
F2
0 0.25 0.5 0.75 1−0.05
−0.025
0
0.025
0.05F7
0.25 0.3 0.35−0.05
−0.025
0
0.025
0.05F2−F7
0 0.25 0.5 0.75 1−0.05
−0.025
0
0.025
0.05
D(m
m)
F3
0 0.25 0.5 0.75 1−0.05
−0.025
0
0.025
0.05F8
0.25 0.3 0.35−0.05
−0.025
0
0.025
0.05F3−F8
0 0.25 0.5 0.75 1−0.05
−0.025
0
0.025
0.05
D(m
m)
F4
0 0.25 0.5 0.75 1−0.05
−0.025
0
0.025
0.05F9
0.25 0.3 0.35−0.05
−0.025
0
0.025
0.05F4−F9
0 0.25 0.5 0.75 1−0.05
−0.025
0
0.025
0.05
t(s)
D(m
m)
F5
0 0.25 0.5 0.75 1−0.05
−0.025
0
0.025
0.05
t(s)
F10
0.25 0.3 0.35−0.05
−0.025
0
0.025
0.05
t(s)
F5−F10
Fig. 4.16 Walls deformations obtained using a low pass filter – EQ1
SERIES 227887 TA Project: DRESBUS II
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0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
D(m
m)
F1
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15F6
0.25 0.3 0.35−0.15
−0.075
0
0.075
0.15F1−F6
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
D(m
m)
F2
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15F7
0.25 0.3 0.35−0.15
−0.075
0
0.075
0.15F2−F7
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
D(m
m)
F3
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15F8
0.25 0.3 0.35−0.15
−0.075
0
0.075
0.15F3−F8
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
D(m
m)
F4
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15F9
0.25 0.3 0.35−0.15
−0.075
0
0.075
0.15F4−F9
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
t(s)
D(m
m)
F5
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
t(s)
F10
0.25 0.3 0.35−0.15
−0.075
0
0.075
0.15
t(s)
F5−F10
Fig. 4.17 Walls deformations obtained using a low pass filter – EQ4
SERIES 227887 TA Project: DRESBUS II
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0 0.075 0.150
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ1
0 0.075 0.150
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ2
0 0.075 0.150
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ3
0 0.075 0.150
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ4
Fig. 4.18 Walls maximum deformations obtained using a low pass filter
SERIES 227887 TA Project: DRESBUS II
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0 0.25 0.5 0.75 1−0.03
−0.015
0
0.015
0.03
t(s)
D(m
m)
D1
0 0.25 0.5 0.75 1−0.03
−0.015
0
0.015
0.03
t(s)
D2
0 0.25 0.5 0.75 1−0.03
−0.015
0
0.015
0.03
t(s)
D3
0 0.25 0.5 0.75 1−0.03
−0.015
0
0.015
0.03
t(s)
D4
0.25 0.3 0.35−0.03
−0.015
0
0.015
0.03
t(s)
D(m
m)
Comparisons
D1 D2 D3 D4
Fig. 4.19 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a low pass filter – EQ1
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
t(s)
D(m
m)
D1
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
t(s)
D2
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
t(s)
D3
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
t(s)
D4
0.2 0.25 0.3−0.15
−0.075
0
0.075
0.15
t(s)
D(m
m)
Comparisons
D1 D2 D3 D4
Fig. 4.20 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a low pass filter – EQ4
SERIES 227887 TA Project: DRESBUS II
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0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
D(m
m)
F1
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15F6
0.25 0.3 0.35−0.15
−0.075
0
0.075
0.15F1−F6
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
D(m
m)
F2
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15F7
0.25 0.3 0.35−0.15
−0.075
0
0.075
0.15F2−F7
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
D(m
m)
F3
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15F8
0.25 0.3 0.35−0.15
−0.075
0
0.075
0.15F3−F8
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
D(m
m)
F4
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15F9
0.25 0.3 0.35−0.15
−0.075
0
0.075
0.15F4−F9
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
t(s)
D(m
m)
F5
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
t(s)
F10
0.25 0.3 0.35−0.15
−0.075
0
0.075
0.15
t(s)
F5−F10
Fig. 4.21 Walls deformations obtained using a band pass filter – EQ4
SERIES 227887 TA Project: DRESBUS II
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0 0.075 0.150
9.5
19
28.5
38
Deformation (mm)D
epth
(mm
)
Left side wallRight side wall
EQ1
0 0.075 0.150
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ2
0 0.075 0.150
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ3
0 0.075 0.150
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ4
Fig. 4.22 Walls maximum deformations obtained using a band pass filter
SERIES 227887 TA Project: DRESBUS II
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0 0.25 0.5 0.75 1−0.1
−0.05
0
0.05
0.1
t(s)
D(m
m)
D1
0 0.25 0.5 0.75 1−0.1
−0.05
0
0.05
0.1
t(s)
D2
0 0.25 0.5 0.75 1−0.1
−0.05
0
0.05
0.1
t(s)
D3
0 0.25 0.5 0.75 1−0.1
−0.05
0
0.05
0.1
t(s)
D4
0.25 0.3 0.35−0.1
−0.05
0
0.05
0.1
t(s)
D(m
m)
Comparisons
D1 D2 D3 D4
Fig. 4.23 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a band pass filter – EQ3
0 100 200 3000
50
100
150
200
250
300
350
Dep
th(m
m)
Force (daN)
Before testAfter test
Fig. 4.24 CPT test results
SERIES 227887 TA Project: DRESBUS II
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0 100 200 300 400 500 600 700 800 900 1000 11000
1
2
3
4
5
6
Sampling point
Set
tlem
ent(
mm
)
S1S2
Fig. 4.25 Soil surface settlements
Stabilization circles
Northridge 0.1g to 0.3g
Sine wavelet
SERIES 227887 TA Project: DRESBUS II
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4.2 TEST DRESBUS_2_2_1
Fig 4.26 presents the model set up along with instrumentation scheme. Tables 4.3 and 4.4
summarize channels and sensors locations before and after the main test. The coordinates refer to
the reference system presented in Fig. 2.21. The settlements estimated for each instrument by the
Figs. 4.27-4.30 show filtered acceleration time histories, while in the Figs. 4.31-4.34 the
maximum horizontal accelerations, obtained along the vertical accelerometer arrays for all
shakes are summarized.
Similar to the first test case, the computed transfer functions did not clearly show the
predominant frequencies of the soil-tunnel system. Moreover, the yawing movement of the ESB
container on the shaking table and the in phase response of the vertical acceleration records on
the tunnel’s roof slab edges were also observed. Similar conclusions are also drawn regarding the
computed shear wave velocity profiles, estimated based to the Zeghal and Elgamal procedure
(Fig. 4.35). Finally, the tunnel deformed in a similar manner with the previous test (Figs. 4.36-
4.40).
CPT tests results obtained before and after the main test are summarized in Fig. 4.41. The results
indicate soil densification during shaking, as reflected in Fig. 4.42. The settlements above the
tunnel were slightly larger compared to the free field, during the stabilization circles, while the
opposite observed during shaking.
SERIES 227887 TA Project: DRESBUS II
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0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A1 − Input
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A2
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A3
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A4
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A5
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A6
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A7
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A8
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A9
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A10
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A11
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A12
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A13
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A14
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A15
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A16
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A17
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A18
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A19
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A20
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A21
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A22
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A23
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A24
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A/4
0g
A25
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A26
Fig. 4.27 Processed acceleration time histories – EQ1
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0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A1 − Input
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A2
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A3
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A4
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A5
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A6
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A7
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A8
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A9
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A10
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A11
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A12
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A13
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A14
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A15
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A16
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A17
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A18
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A19
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A20
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A21
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A22
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A23
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A24
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A/4
0g
A25
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A26
Fig. 4.28 Processed acceleration time histories – EQ2
SERIES 227887 TA Project: DRESBUS II
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0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A/4
0g
A1 − Input
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A2
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A3
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A4
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A5
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A6
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A/4
0g
A7
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A8
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A9
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A10
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A11
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A12
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A/4
0g
A13
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A14
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A15
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A16
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A17
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A18
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A/4
0g
A19
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A20
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A21
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A22
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A23
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A24
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A/4
0g
A25
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A26
Fig. 4.29 Processed acceleration time histories – EQ3
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0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A/4
0g
A1 − Input
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A2
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A3
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A4
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A5
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A6
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A/4
0g
A7
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A8
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A9
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A10
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A11
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A12
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A/4
0g
A13
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A14
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A15
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A16
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A17
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A18
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A/4
0g
A19
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A20
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
t(s)
A21
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
t(s)
A22
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
t(s)
A23
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
t(s)
A24
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
t(s)
A/4
0g
A25
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
t(s)
A26
Fig. 4.30 Processed acceleration time histories – EQ4
SERIES 227887 TA Project: DRESBUS II
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0 0.07 0.14 0.21 0.280
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 1 − A/40g0 0.07 0.14 0.21 0.28
0
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.07 0.14 0.21 0.28
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.07 0.14 0.21 0.28
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.07 0.14 0.21 0.280
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.05 0.1 0.15 0.2 0.30.05
0.06
0.07
0.08
0.09
0.1D
epth
(m)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.31 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ1
0 0.1 0.2 0.3 0.40
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 1 − A/40g0 0.1 0.2 0.3 0.4
0
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.1 0.2 0.3 0.4
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.1 0.2 0.3 0.4
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.1 0.2 0.3 0.40
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.15 0.2 0.25 0.3 0.35 0.40.05
0.06
0.07
0.08
0.09
0.1
Dep
th(m
)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.32 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ2
SERIES 227887 TA Project: DRESBUS II
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0 0.15 0.3 0.45 0.60
0.09
0.18
0.27
0.36
Dep
th(m
)Array 1 − A/40g
0 0.15 0.3 0.45 0.60
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.15 0.3 0.45 0.6
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.15 0.3 0.45 0.6
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.15 0.3 0.45 0.60
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.25 0.3 0.35 0.4 0.45 0.50.05
0.06
0.07
0.08
0.09
0.1D
epth
(m)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.33 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. – EQ3
0 0.2 0.4 0.6 0.80
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 1 − A/40g0 0.2 0.4 0.6 0.8
0
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.2 0.4 0.6 0.8
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.2 0.4 0.6 0.8
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.2 0.4 0.6 0.80
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.3 0.4 0.5 0.6 0.7 0.80.05
0.06
0.07
0.08
0.09
0.1
Dep
th(m
)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.34 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ4
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0 100 200 300 4000
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
Dep
th(m
)Vs(m/s)
Array 2Array 4Array 5Hardin & Drenvich, 1972
EQ1
0 100 200 300 4000
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
Dep
th(m
)
Vs(m/s)
Array 2Array 4Array 5Hardin & Drenvich, 1972
EQ2
0 100 200 300 4000
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
Dep
th(m
)
Vs(m/s)
Array 2Array 4Array 5Hardin & Drenvich, 1972
EQ3
0 100 200 300 4000
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
Dep
th(m
)
Vs(m/s)
Array 2Array 4Array 5Hardin & Drenvich, 1972
EQ4
Fig. 4.35 Shear wave velocity profiles computed along vertical accelerometers arrays; comparison with Vso computed according to Hardin and Drenvich (1972) formulation
SERIES 227887 TA Project: DRESBUS II
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0 0.25 0.5 0.75 1−0.08
−0.04
0
0.04
0.08
D(m
m)
F1
0 0.25 0.5 0.75 1−0.08
−0.04
0
0.04
0.08F6
0.25 0.3 0.35−0.08
−0.04
0
0.04
0.08F1−F6
0 0.25 0.5 0.75 1−0.08
−0.04
0
0.04
0.08
D(m
m)
F2
0 0.25 0.5 0.75 1−0.08
−0.04
0
0.04
0.08F7
0.25 0.3 0.35−0.08
−0.04
0
0.04
0.08F2−F7
0 0.25 0.5 0.75 1−0.08
−0.04
0
0.04
0.08
D(m
m)
F3
0 0.25 0.5 0.75 1−0.08
−0.04
0
0.04
0.08F8
0.25 0.3 0.35−0.08
−0.04
0
0.04
0.08F3−F8
0 0.25 0.5 0.75 1−0.08
−0.04
0
0.04
0.08
D(m
m)
F4
0 0.25 0.5 0.75 1−0.08
−0.04
0
0.04
0.08F9
0.25 0.3 0.35−0.08
−0.04
0
0.04
0.08F4−F9
0 0.25 0.5 0.75 1−0.08
−0.04
0
0.04
0.08
t(s)
D(m
m)
F5
0 0.25 0.5 0.75 1−0.08
−0.04
0
0.04
0.08
t(s)
F10
0.25 0.3 0.35−0.08
−0.04
0
0.04
0.08
t(s)
F5−F10
Fig. 4.36 Walls deformations obtained using a low pass filter – EQ2
SERIES 227887 TA Project: DRESBUS II
61
0 0.075 0.150
9.5
19
28.5
38
Deformation (mm)D
epth
(mm
)
Left side wallRight side wall
EQ1
0 0.075 0.150
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ2
0 0.075 0.150
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ3
0 0.075 0.150
9.5
19
28.5
38
Deformation (mm)D
epth
(mm
)
Left side wallRight side wall
EQ4
Fig. 4.37 Walls maximum deformations obtained using a low pass filter
SERIES 227887 TA Project: DRESBUS II
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0 0.25 0.5 0.75 1−0.03
−0.015
0
0.015
0.03
t(s)
D(m
m)
D1
0 0.25 0.5 0.75 1−0.03
−0.015
0
0.015
0.03
t(s)
D2
0 0.25 0.5 0.75 1−0.03
−0.015
0
0.015
0.03
t(s)
D3
0 0.25 0.5 0.75 1−0.03
−0.015
0
0.015
0.03
t(s)
D4
0.25 0.3 0.35−0.03
−0.015
0
0.015
0.03
t(s)
D(m
m)
Comparisons
D1 D2 D3 D4
Fig. 4.38 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a low pass filter – EQ3
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
t(s)
D(m
m)
D1
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
t(s)
D2
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
t(s)
D3
0 0.16 0.32 0.48 0.64−0.15
−0.075
0
0.075
0.15
t(s)
D4
0.25 0.3 0.35−0.15
−0.075
0
0.075
0.15
t(s)
D(m
m)
Comparisons
D1 D2 D3 D4
Fig. 4.39 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a band pass filter – EQ4
SERIES 227887 TA Project: DRESBUS II
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0 0.075 0.150
9.5
19
28.5
38
Deformation (mm)D
epth
(mm
)
Left side wallRight side wall
EQ1
0 0.075 0.150
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ2
0 0.075 0.150
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ3
0 0.075 0.150
9.5
19
28.5
38
Deformation (mm)D
epth
(mm
)
Left side wallRight side wall
EQ4
Fig. 4.40 Walls maximum deformations obtained using a band pass filter
SERIES 227887 TA Project: DRESBUS II
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0 100 200 3000
50
100
150
200
250
300
350
Dep
th(m
m)
Force (daN)
Before test
Fig. 4.41 CPT test results
0 100 200 300 400 500 600 700 800 9000
1
2
3
4
5
6
7
8
Sampling point
Set
tlem
ent(
mm
)
S1S2S3
Fig. 4.42 Soil surface settlements
Stabilization circles
Northridge 0.1g to 0.3g
Sine wavelet
SERIES 227887 TA Project: DRESBUS II
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4.3 TEST DRESBUS_2_3_1
Fig 4.43 presents the model set up along with instrumentation scheme, while Tables 4.5 and 4.6
summarize channels and sensors locations before and after the main test.
Similar observations with the previous tests are made regarding the transfer functions, the
vertical acceleration and the Vs profiles. Although the rigid tunnel deformed less than the flexible
tunnels, similar observations were made for the tunnel deformations, namely: increase of the
walls deformations reaching the roof slab, increase of the tunnel deformations with the increase
of the input motion amplitude and in phase response of the diagonal deformations (Figs. 4.53-
4.58).
CPT tests results obtained before and after the main test are summarized in Fig. 4.59. The results
indicate soil densification during shaking, as reflected in Fig. 4.60.
SERIES 227887 TA Project: DRESBUS II
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0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A1 − Input
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A2
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A3
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A4
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A5
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A6
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A7
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A8
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A9
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A10
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A11
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A12
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A13
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A14
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A15
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A16
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A17
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A18
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A/4
0g
A19
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
A20
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A21
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A22
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A23
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A24
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A/4
0g
A25
0 0.25 0.5 0.75 1−0.3
−0.150
0.150.3
t(s)
A26
Fig. 4.44 Processed acceleration time histories – EQ1
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0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A1 − Input
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A2
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A3
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A4
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A5
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A6
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A7
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A8
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A9
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A10
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A11
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A12
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A13
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A14
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A15
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A16
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A17
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A18
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A/4
0g
A19
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
A20
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A21
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A22
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A23
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A24
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A/4
0g
A25
0 0.25 0.5 0.75 1−0.4−0.2
00.20.4
t(s)
A26
Fig. 4.45 Processed acceleration time histories – EQ2
SERIES 227887 TA Project: DRESBUS II
70
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A/4
0g
A1 − Input
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A2
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A3
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A4
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A5
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A6
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A/4
0g
A7
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A8
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A9
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A10
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A11
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A12
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A/4
0g
A13
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A14
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A15
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A16
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A17
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A18
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A/4
0g
A19
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
A20
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A21
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A22
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A23
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A24
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A/4
0g
A25
0 0.25 0.5 0.75 1−0.5
−0.250
0.250.5
t(s)
A26
Fig. 4.46 Processed acceleration time histories – EQ3
SERIES 227887 TA Project: DRESBUS II
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0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A/4
0g
A1 − Input
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A2
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A3
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A4
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A5
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A6
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A/4
0g
A7
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A8
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A9
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A10
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A11
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A12
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A/4
0g
A13
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A14
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A15
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A16
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A17
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A18
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A/4
0g
A19
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
A20
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
t(s)
A21
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
t(s)
A22
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
t(s)
A23
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
t(s)
A24
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
t(s)
A/4
0g
A25
0 0.16 0.32 0.48 0.64−0.8−0.4
00.40.8
t(s)
A26
Fig. 4.47 Processed acceleration time histories – EQ4
SERIES 227887 TA Project: DRESBUS II
72
0 0.07 0.14 0.21 0.280
0.09
0.18
0.27
0.36
Dep
th(m
)Array 1 − A/40g
0 0.07 0.14 0.21 0.280
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.07 0.14 0.21 0.28
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.07 0.14 0.21 0.28
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.07 0.14 0.21 0.280
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.1 0.2 0.3 0.40.05
0.06
0.07
0.08
0.09
0.1D
epth
(m)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.48 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ1
0 0.1 0.2 0.3 0.40
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 1 − A/40g0 0.1 0.2 0.3 0.4
0
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.1 0.2 0.3 0.4
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.1 0.2 0.3 0.4
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.1 0.2 0.3 0.40
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.15 0.25 0.35 0.450.05
0.06
0.07
0.08
0.09
0.1
Dep
th(m
)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.49 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ2
SERIES 227887 TA Project: DRESBUS II
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0 0.125 0.25 0.375 0.50
0.09
0.18
0.27
0.36
Dep
th(m
)Array 1 − A/40g
0 0.125 0.25 0.375 0.50
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.125 0.25 0.375 0.5
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.125 0.25 0.375 0.5
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.125 0.25 0.375 0.50
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.25 0.35 0.45 0.550.05
0.06
0.07
0.08
0.09
0.1D
epth
(m)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.50 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ3
0 0.2 0.4 0.6 0.80
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 1 − A/40g0 0.2 0.4 0.6 0.8
0
0.09
0.18
0.27
0.36
Array 2 − A/40g0 0.2 0.4 0.6 0.8
0
0.09
0.18
0.27
0.36
Array 3 − A/40g0 0.2 0.4 0.6 0.8
0
0.09
0.18
0.27
0.36
Array 4 − A/40g
0 0.2 0.4 0.6 0.80
0.09
0.18
0.27
0.36
Dep
th(m
)
Array 5 − A/40g 0.35 0.45 0.55 0.650.05
0.06
0.07
0.08
0.09
0.1
Dep
th(m
)
A/40g @ tunnel depth
Array 1Array 2Array 3Array 4Array 5
Fig. 4.51 Maximum horizontal acceleration along the vertical accelerometer arrays (arrays according to Fig. 4.2) – EQ4
SERIES 227887 TA Project: DRESBUS II
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0 100 200 300 4000
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
Dep
th(m
)Vs(m/s)
Array 2Array 4Array 5Hardin & Drenvich, 1972
EQ1
0 100 200 300 4000
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
Dep
th(m
)
Vs(m/s)
Array 2Array 4Array 5Hardin & Drenvich, 1972
EQ2
0 100 200 300 4000
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
Dep
th(m
)
Vs(m/s)
Array 2Array 4Array 5Hardin & Drenvich, 1972
EQ3
0 100 200 300 4000
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
Dep
th(m
)
Vs(m/s)
Array 2Array 4Array 5Hardin & Drenvich, 1972
EQ4
Fig. 4.52 Shear wave velocity profiles computed along vertical accelerometers arrays; comparison with Vso computed according to Hardin and Drenvich (1972) formulation
SERIES 227887 TA Project: DRESBUS II
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0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
D(m
m)
F1
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01F6
0.25 0.3 0.35−0.01
−0.005
0
0.005
0.01F1−F6
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
D(m
m)
F2
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01F7
0.25 0.3 0.35−0.01
−0.005
0
0.005
0.01F2−F7
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
D(m
m)
F3
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01F8
0.25 0.3 0.35−0.01
−0.005
0
0.005
0.01F3−F8
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
D(m
m)
F4
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01F9
0.25 0.3 0.35−0.01
−0.005
0
0.005
0.01F4−F9
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
t(s)
D(m
m)
F5
0 0.25 0.5 0.75 1−0.01
−0.005
0
0.005
0.01
t(s)
F10
0.25 0.3 0.35−0.01
−0.005
0
0.005
0.01
t(s)
F5−F10
Fig. 4.53 Walls deformations obtained using a low pass filter – EQ1
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0 0.16 0.32 0.48 0.64−0.03
−0.015
0
0.015
0.03
D(m
m)
F1
0 0.16 0.32 0.48 0.64−0.03
−0.015
0
0.015
0.03F6
0.25 0.3 0.35−0.03
−0.015
0
0.015
0.03F1−F6
0 0.16 0.32 0.48 0.64−0.03
−0.015
0
0.015
0.03
D(m
m)
F2
0 0.16 0.32 0.48 0.64−0.03
−0.015
0
0.015
0.03F7
0.25 0.3 0.35−0.03
−0.015
0
0.015
0.03F2−F7
0 0.16 0.32 0.48 0.64−0.03
−0.015
0
0.015
0.03
D(m
m)
F3
0 0.16 0.32 0.48 0.64−0.03
−0.015
0
0.015
0.03F8
0.25 0.3 0.35−0.03
−0.015
0
0.015
0.03F3−F8
0 0.16 0.32 0.48 0.64−0.03
−0.015
0
0.015
0.03
D(m
m)
F4
0 0.16 0.32 0.48 0.64−0.03
−0.015
0
0.015
0.03F9
0.25 0.3 0.35−0.03
−0.015
0
0.015
0.03F4−F9
0 0.16 0.32 0.48 0.64−0.03
−0.015
0
0.015
0.03
t(s)
D(m
m)
F5
0 0.16 0.32 0.48 0.64−0.03
−0.015
0
0.015
0.03
t(s)
F10
0.25 0.3 0.35−0.03
−0.015
0
0.015
0.03
t(s)
F5−F10
Fig. 4.54 Walls deformations obtained using a low pass filter – EQ4
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0 0.025 0.050
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ1
0 0.025 0.050
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ2
0 0.025 0.050
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ3
0 0.025 0.050
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ4
Fig. 4.55 Walls maximum deformations obtained using a low pass filter
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0 0.25 0.5 0.75 1−0.05
−0.025
0
0.025
0.05
t(s)
D(m
m)
D1
0 0.25 0.5 0.75 1−0.05
−0.025
0
0.025
0.05
t(s)
D2
0 0.25 0.5 0.75 1−0.05
−0.025
0
0.025
0.05
t(s)
D3
0 0.25 0.5 0.75 1−0.05
−0.025
0
0.025
0.05
t(s)
D4
0.25 0.3 0.35−0.05
−0.025
0
0.025
0.05
t(s)
D(m
m)
Comparisons
D1 D2 D3 D4
Fig. 4.56 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a low pass filter – EQ2
0 0.16 0.32 0.48 0.64−0.08
−0.04
0
0.04
0.08
t(s)
D(m
m)
D1
0 0.16 0.32 0.48 0.64−0.08
−0.04
0
0.04
0.08
t(s)
D2
0 0.16 0.32 0.48 0.64−0.08
−0.04
0
0.04
0.08
t(s)
D3
0 0.16 0.32 0.48 0.64−0.08
−0.04
0
0.04
0.08
t(s)
D4
0.25 0.3 0.35−0.08
−0.04
0
0.04
0.08
t(s)
D(m
m)
Comparisons
D1 D2 D3 D4
Fig. 4.57 Diagonal tunnel deformations obtained along several locations of the tunnel axis using a band pass filter – EQ4
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0 0.025 0.050
9.5
19
28.5
38
Deformation (mm)D
epth
(mm
)
Left side wallRight side wall
EQ1
0 0.025 0.050
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ2
0 0.025 0.050
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ3
0 0.025 0.050
9.5
19
28.5
38
Deformation (mm)
Dep
th(m
m)
Left side wallRight side wall
EQ4
Fig. 4.58 Walls maximum deformations obtained using a band pass filter
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0 100 200 3000
50
100
150
200
250
300
350
Dep
th(m
m)
Force (daN)
Before test
Fig. 4.59 CPT test results
0 200 400 600 800 1000 12000
1
2
3
4
5
6
7
8
Sampling point
Set
tlem
ent(
mm
)
S1S2S3
Fig. 4.60 Soil surface settlements
4.4 TEST DRESBUS_2_4_1
This test was the first in saturated sand. The tunnel ends were formed following the configuration
presented in Fig 2.12b. This configuration did not manage to withstand the water pressures
during the tests, leading to water leakage inside the tunnel and subsequently to problems to the
extensometers that did not work properly.
Stabilization circles
Northridge 0.1g to 0.3g
Sine wavelet
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4.5 TEST DRESBUS_2_4_2
This test was a repetition of the test DRESBUS_2_4_1. Fig 4.61 presents the model set up along
with instrumentation scheme. The viscosity of the saturation fluid was formulated for a
temperature of 14°C which was verified to be consistent with the temperature in the centrifuge
room. The resulting viscosity was controlled just before the test to be between 39 and 40 cSt.
Fig. 5.2 Maximum horizontal acceleration at the soil free field (Array 2) for the dry tests
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0 0.1125 0.225 0.3375 0.450
0.09
0.18
0.27
0.36
Dep
th(m
)
A/40g − EQ10 0.1125 0.225 0.3375 0.45
0
0.09
0.18
0.27
0.36
Dep
th(m
)
A/40g − EQ2
0 0.1125 0.225 0.3375 0.450
0.09
0.18
0.27
0.36
Dep
th(m
)
A/40g − EQ3
0 0.1125 0.225 0.3375 0.450
0.09
0.18
0.27
0.36
Dep
th(m
)
A/40g − EQ4
DRESBUS 2 4 2DRESBUS 2 6 1DRESBUS 2 7 1
Fig. 5.3 Maximum horizontal acceleration at the soil free field (Array 2) for the saturated tests
5.3 TUNNELS RACKING DEFORMATIONS
The following paragraphs present comparisons of the maximum deformations recorded on the
tunnels walls as affected by (i) the input motion amplitude, (ii) the rigidity of the tunnel and (iii)
the roughness of the tunnel’s external face.
5.3.1 Input motion amplitude effect
Figs. 5.4-5.10 show maximum racking deformations imposed on the tunnels side walls (lsw: left
side wall, rsw: right side wall) for each test case. EQ1, EQ2 and EQ3 refer to the Northridge
record scaled to 0.1 g, 0.2 g and 0.3 g, respectively, whereas EQ4 refers to the sine wavelet (0.3
g, 85 Hz). Generally, the racking deformations are increased with increasing amplitude of the
base excitation in a symmetrical manner between the two side walls of the tunnel section. It is
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noted that the tunnel response recorded during tests DRESBUS_4_2_2 and DRESBUS_2_5_1
was partially corrupted.
0 0.05 0.1 0.150
9.5
19
28.5
38
Dep
th(m
m)
0 0.05 0.1 0.15 0.2
EQ1EQ2EQ3EQ4
D(mm)
lsw rsw
Fig. 5.4 Maximum racking deformations for different input motion amplitudes – rough flexible tunnel in dry sand (DRESBUS2_1_1)
0 0.05 0.1 0.150
9.5
19
28.5
38
Dep
th(m
m)
0 0.05 0.1 0.15 0.2
EQ1EQ2EQ3EQ4
D(mm)
lsw rsw
Fig. 5.5 Maximum racking deformations for different input motion amplitudes – smooth flexible tunnel in dry sand (DRESBUS2_2_1)
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0 0.0063 0.0125 0.01880
9.5
19
28.5
38
Dep
th(m
m)
0 0.0063 0.0125 0.0188 0.025
EQ1EQ2EQ3EQ4
D(mm)
lsw rsw
Fig. 5.6 Maximum racking deformations for different input motion amplitudes – rough rigid tunnel in dry sand (DRESBUS2_3_1)
0 0.0063 0.0125 0.01880
9.5
19
28.5
38
Dep
th(m
m)
0 0.0063 0.0125 0.0188 0.025
EQ1EQ2EQ3EQ4
D(mm)
lsw rsw
Fig. 5.7 Maximum racking deformations for different input motion amplitudes – rough rigid tunnel in saturated sand (DRESBUS2_4_2)
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0 0.15 0.3 0.450
9.5
19
28.5
38
Dep
th(m
m)
0 0.15 0.3 0.45 0.6
EQ1EQ2EQ3EQ4
D(mm)
lsw rsw
Fig. 5.8 Maximum racking deformations for different input motion amplitudes – smooth rigid tunnel in dry sand (DRESBUS2_5_1)
0 0.0063 0.0125 0.01880
9.5
19
28.5
38
Dep
th(m
m)
0 0.0063 0.0125 0.0188 0.025
EQ1EQ2EQ3EQ4
D(mm)
lsw rsw
Fig. 5.9 Maximum racking deformations for different input motion amplitudes – smooth rigid tunnel in saturated sand (DRESBUS2_6_1)
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0 0.0063 0.0125 0.01880
9.5
19
28.5
38
Dep
th(m
m)
0 0.0063 0.0125 0.0188 0.025
EQ1EQ2EQ3EQ4
D(mm)
lsw rsw
Fig. 5.10 Maximum racking deformations for different input motion amplitudes – rough rigid tunnel in saturated sand (DRESBUS2_7_1)
5.3.2 Tunnel stiffness effect
Notwithstanding the similar deformation pattern, the flexible tunnel sections showed higher
deformation amplitudes compared to the rigid ones.
5.3.3 Soil‐tunnel interface effect
Fig 5.11 compares wall deformations for smooth and rough soil-tunnel interface. The results
refer to the flexible tunnel case embedded in dry sand (tests DRESBUS2_1_1,
DRESBUS2_2_1). A similar deformation pattern is revealed, while larger deformation amplitude
is observed for the smooth surface tunnel under the low-amplitude base excitations (EQ1 and
EQ2). The opposite trend is observed for the high-amplitude motions (EQ3 and EQ4) were the
deformations of the rough surface tunnel are generally larger than the smooth interface tunnel.
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0 0.0375 0.075 0.11250
9.5
19
28.5
38
Dep
th(m
m)
0 0.0375 0.075 0.1125 0.15
0 0.0375 0.075 0.11250
9.5
19
28.5
38
Dep
th(m
m)
0 0.0375 0.075 0.1125 0.15
0 0.0375 0.075 0.11250
9.5
19
28.5
38
Dep
th(m
m)
0 0.0375 0.075 0.1125 0.15
0 0.0375 0.075 0.11250
9.5
19
28.5
38
Dep
th(m
m)
0 0.0375 0.075 0.1125 0.15
RoughSmooth
EQ1 − D(mm)
EQ2 − D(mm)
EQ3 − D(mm)
EQ4 − D(mm)
lsw rsw
Fig. 5.11 Maximum racking deformations for different input motion amplitudes – rough vs. smooth flexible tunnel in dry sand (DRESBUS2_1_1 vs. DRESBUS2_2_1)
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Comparisons of the walls deformations as recorded for the rigid tunnels embedded in saturated
sands are summarized in Fig. 5.12 (test case DRESBUS_2_6_1: smooth tunnel,
DRESBUS_2_7_1: rough tunnel). The wall deformations were generally larger for the rough
tunnel, with the difference being increased with the increase of the input motion amplitude.
0 0.005 0.01 0.0150
9.5
19
28.5
38
Dep
th(m
m)
0 0.005 0.01 0.015 0.02
0 0.005 0.01 0.0150
9.5
19
28.5
38
Dep
th(m
m)
0 0.005 0.01 0.015 0.02
0 0.005 0.01 0.0150
9.5
19
28.5
38
Dep
th(m
m)
0 0.005 0.01 0.015 0.02
0 0.005 0.01 0.0150
9.5
19
28.5
38
Dep
th(m
m)
0 0.005 0.01 0.015 0.02
RoughSmooth
EQ1 − D(mm)
EQ2 − D(mm)
EQ3 − D(mm)
EQ4 − D(mm)
lsw rsw
Fig. 5.12 Maximum racking deformations for different input motion amplitudes – rough vs. smooth rigid tunnel in saturated sand (DRESBUS2_6_1 vs. DRESBUS2_7_1)
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5.3.4 Soil saturation effect
Fig 5.13 presents the effect of the sand saturation on the wall deformations as recorded for the
rigid tunnel having a rough external face (tests DRESBUS2_3_1: dry sand, DRESBUS2_2_1:
saturated sand). The walls deformations found to be systematically larger for the dry sand case.
This observation may be attributed to some extend to the higher sand stiffness of the dry sand
compared to the saturated case.
0 0.0075 0.015 0.02250
9.5
19
28.5
38
Dep
th(m
m)
0 0.0075 0.015 0.0225 0.03
0 0.0075 0.015 0.02250
9.5
19
28.5
38
Dep
th(m
m)
0 0.0075 0.015 0.0225 0.03
0 0.0075 0.015 0.02250
9.5
19
28.5
38
Dep
th(m
m)
0 0.0075 0.015 0.0225 0.03
0 0.0075 0.015 0.02250
9.5
19
28.5
38
Dep
th(m
m)
0 0.0075 0.015 0.0225 0.03
DrySaturated
EQ1 − D(mm)
EQ2 − D(mm)
EQ3 − D(mm)
EQ4 − D(mm)
lsw rsw
Fig. 5.13 Maximum racking deformations for different input motion amplitudes – effect of sand saturation (DRESBUS2_3_1 vs. DRESBUS2_7_1)
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6 Conclusions
This report included a detailed description of the centrifuge tests performed within the SERIES
TA Project: DRESBUS II: Investigation of the seismic behaviour of shallow rectangular
underground structures in soft soils using centrifuge experiments. Experimental procedures and
data processing methods were described followed by a detailed presentation of the complete set
of the recorded data. The preliminary interpretation of the results revealed the following issues:
Maximum soil horizontal accelerations were increased within the soil deposit indicating
base-to-surface soil amplification effects.
In some test cases, maximum tunnel acceleration recorded on the base slab was larger
than the corresponding value recorded on the roof slab. This counterintuitive behavior
may be associated with recording spikes that were observed after filtering.
The horizontal deformations along the tunnels side walls developed in a symmetrical
manner proving the theoretical assumption of racking distortion mode.
The diagonal extensometers recordings showed in-phase diagonal deformations along the
longitudinal axis of the tunnel denoting the plane strain behavior of the model sections.
Rigid tunnels were understandably less deformed during shaking compared to the flexible
sections.
For the specific soil-tunnel systems under investigation, the external face rugosity seems
to have a minor effect on the tunnels deformation, probably due to the small dimensions
of the test models.
Tunnel walls deformations were generally larger for the dry test case compared to the
saturated case. This observation may be attributed to some extend to the higher sand
stiffness of the dry sand compared to the saturated case.
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References
Brennan, A.J., Thusyanthan, N.I. and Madabhushi S.P.G. 2005. Evaluation of shear modulus and damping in