Geotechnics 2013 in the Piedmont -MAYNE - Geosystem …geosystems.ce.gatech.edu/abstracts/Sowers2013_Mayne.pdf · Solution Fairfax Hospital ... Case Study: First American Bank, Northern
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5/13/2013
1
Geotechnics 2013 in the Atlantic Piedmont Province
Paul W. Mayne, PhD, P.E.Georgia Institute of Technology
07 May 2013
The 16th Annual Sowers LectureGeorge F. Sowers(1921 – 1996)
Professor, Civil and Environmental Engineering, Georgia Tech
Senior Consultant, Law Engineering Testing Company (LETCO→ MACTEC → AMEC)
• Introduction to Soil Mechanics & Foundations (MacMillan: 1951, 1961, 1970, 1979) – English, Spanish, Chinese
• Building on Sinkholes (ASCE 1996)
Awards ‐ George F. Sowers
Engineer of the Year 1973 – GSPE
Herschel Prize 1976 – Boston SCE
ASCE Middlebrooks Award 1977
ASCE Terzaghi Lecture 1979
ASCE Martin Kapp Lecture 1985
Brooks Award in 1990
ASCE Middlebrooks Award 1994
Elected to National Academy of Engineering 1994
ASCE Terzaghi Award 1995
George F. Sowers Quotes:
Reston Dam, VA CIA, McLean, Virginia Pennfield PA
“An earth dam is likea beautiful woman…….”
“Its one dam projectafter another” “Working at the
CIA is a huge PIA”
“Using drilled shafts vs. driven pilings in karst is like
the difference of being hung or being shot. Either
way you are screwed”
Concerns after Teton Dam Failed High K0 stresses on basement walls Karst Limestone
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LETCO in Thule, Greenland 1984 1952Magnetic North Pole 1984
LETCO in Thule, GreenlandSatellite Tracking Antenna for Ford Aerospace
Jefferson Accelerator ‐ JLAB(CEBAF) – Newport News, Virginia
Nuclear physics experimental hall for study of hadrons and quarks 1800 electromagnets in an elliptical ring for high‐energy beam Tolerate only 3 mm differential between adjacent units per month
Jefferson Accelerator ‐ JLAB(CEBAF) – Newport News, Virginia Embankment
Over Tunnel
Minimize primaryconsolidation
settlements and long‐term creep
Jefferson Accelerator ‐ JLAB(CEBAF) – Newport News, Virginia
Georgia Tech Geotechs Co‐Taught CE 6159 Rock Mechanics (1991, 1995) Textbook: Goodman, R.E. (Dick gave 3rd Sowers Lecture) Classes in Old Highway Lab Tour of rock tunnels at Duke Power Energy Station Sowers, G.F. (1996): Building on Sinkholes, ASCE Press
ASCE Interview with Professor Sowers: "How long did it take you to write this book"
George answered: "My whole life"
GT Geotechnical EngineeringMonie Ferst Award (1994) to J. Mike Duncan
Wayne Clough1st Sowers Lecture
Mike Duncan2nd Sowers Lecture
GeorgeSowers
Terzaghi Lectures by GT Geotechs
16
1979 ‐ George F. Sowers "There were Giants on the Earth in those days"
1994 ‐ G. Wayne Clough"Soft Ground Tunneling"
2014 ‐ J. Carlos SantamarinaASCE GeoCongress ‐ Atlanta
George F. SowersFamous for:
Case Studies
Lessons Learned
Importance of Engineering Geology
Practical Aspects of Geotechnical Engineering
Be careful, cautious, and stand your ground
Tell it like it is
Anecdotes
Geotechnics 2013 in the Piedmont
State‐of‐the‐Art (SOA) = What we COULD be doing: Guney Olgun
State‐of‐the‐Practice (SOP) = what we ARE doing: Ken Been
Limited time, so focus on Geocharacterizationfor Foundation Systems in the Piedmont
Era Period Epoch Time Boundaries (Years Ago) Holocene - Recent Quaternary 10,000 Pleistocene 2 million Pliocene 5 million Cenozoic Miocene 26 million Tertiary Oligocene 38 million Eocene 54 million Paleocene 65 million Cretaceous 130 million Mesozoic Jurassic 185 million Triassic 230 million Permian 265 million Pennsylvanian Carboniferous 310 million Mississippian 355 million Paleozoic Devonian 413 million Silurian 425 million Ordovician 475 million Cambrian 570 million Precambrian 3.9 billion Earth Beginning 4.7 billion
PiedmontGneiss
and Schist
PiedmontGranite
Z‐Age ≈ 1 billion years ago
Piedmont Residuum: a.k.a. “Georgia Red Clay”
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Piedmont Subsurface Profile
"Georgia Red Clay"(CL ‐ML)
RESIDUUM (ML to SM)
SAPROLITE
Partially‐WeatheredRock (PWR)
Intact Rock: GneissSchist, Granite
GT Load Test Site, West Campus
0
10
20
30
40
50
60
70
80
0 10 20 30 40 50 60 70 80 90 100
SPT N-values (bpf)
Dep
th (fe
et)
GRANITIC GNEISS
Piedmont Residuum:Silty Fine Sand (SM)
PWR
Major Rock Formations in USA
Piedmont
In‐Situ Testing in the Piedmont• SPT = standard penetration testing
• PMT = pressuremeter testing
• DP = dynamic penetrometers
• percussive soundings (air‐track)
• VST = vane shear testing
• DMT = flat plate dilatometer
• CPT = cone penetration testing
• CPTu = piezocone testing
• Vs = shear wave velocity
• SCPTu = seismic piezocone
• SDMT = seismic dilatometer
Miller & Sowers (1967). Shear characteristics of
Piedmont soils using rotating vanes
SCPTU in Piedmont residual siltsWinston‐Salem, NC
Fairfax Hospital, Northern Virginia (1984)Case Study: Drilled shaft (L = 65' and d = 3') in Piedmont residuum
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Axial Pile Influence Factors (Rigid Pile)
Randolph & Wroth (1979); Poulos & Davis (1980)
Rigid Pile in an Infinite Elastic Medium
0.01
0.10
1.00
0 10 20 30 40 50 60 70 80 90 100
Slenderness Ratio, L/d
Infl
uen
ce F
act
or,
I o
Boundary Elements
Closed Form v = 0.5
Closed Form v = 0.2
Closed Form v = 0s
ptt Ed
IPw
Poulos & Davis (1980) Solution vs. Randolph Solution
Pt = load at top = Ps + Pb
Homogeneous Soil: Es = Elastic modulus' = Poisson's ratio
RIGID PILE RESPONSELength L and diameter d
Side Load, Ps= Pt ‐ Pb
Top Displacement, wt
s
tt Ed
IPw
Load Transfered to Base:
)]1)(/(5ln[)/(
)1(1
11
2 vdLdL
I
21
I
P
P
t
bPb = Base load
Ground Surface
Randolph Solution
Fairfax Hospital, Northern Virginia
s
ptt Ed
IPw
E' ≈ ED (ave. 64 DMTs) = 35 MPa = 364 tsfL = 65 feet and d = 3 feetRatio L/d = 21.7 Ip = 0.076
Buildings on Piedmont ‐ Northern Virginia and Washington DC
DMT‐SPT Correlation in Piedmont Residuum(Mayne & Frost, TRR 1988) Also EPRI Manual (1990)
Foundation Systems in the Piedmont Spread footings
Mat foundations
Augercast pilings
Drilled shafts
Micropiles
Driven pipe piles
H‐pilings
Monotubes
Step‐taper piles
Franki piles (PIFs)
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Case Study: First American Bank, Northern Virginia Case Study: First American Bank, Northern Virginia
Franki Piles, a.k.a. "Pressure Injected Footings"
Compacted Bulbof Zero‐SlumpConcrete
Pipe Casing
Concrete Shaft
Base
Case Study: Lincoln Center, Fairfax County, VA
150 Franki Piles Installed
Load Test → 5" settlement
Mat Foundation (raft)
Geotechnical Meeting• Dames & Moore• Law Engineering• Woodward-Clyde• Schnabel Engineering• ASCE National
Geotechnical Section
• No more PIFs in NoVA• Also, no law suit
First AmericanBank Mat
22-story Bank Building - Mat Foundation Tysons Corner, Virginia
0
50
100
150
200
0 50 100 150 200
West Side (feet)
No
rth
Sid
e (
feet
)
Structural ReinforcedConcrete Mat Foundation: t = 4.5 feet
FULL‐SCALE LOAD TESTS Drilled shaft foundations Axial tests on drilled shafts Lateral tests on drilled shafts Time and construction effects studies Driven pipe piles at varied rates De Waal piles Lateral loading testing of pile groups Shafts with self‐compacting concrete
Opelika NGES, Alabama ‐ Piedmont Residuum
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CPTu in Piedmont PWR‐ Atlanta, GA
SPTN6023
34
71
34
56
67
50/6"
50/6"
50/2"
50/3"
0
2
4
6
8
10
12
14
0 10 20 30 40 50 60
qT (MPa)
Dep
th (
m)
0 0.2 0.4 0.6 0.8 1
fs (MPa)
-0.1 -0.05 0 0.05 0.1
u2 (MPa)
Partially‐
Weathered
Rock
(gneiss)
Saprolite
(hard fine
sandy silt)
Residuum:
silty fine
sand
Combo CPT‐Drill Rig
CPTDrill/SPT
SCPTU in Piedmont residual siltsWinston‐Salem, NC
Geotechnics 2013 in the Piedmont
More Measurements
is
More Better
Mas Mejor
Seismic Piezocone (SCPTu)Piedmont silts in Marietta, GA
Tip Resistance
0
2
4
6
8
10
12
14
16
18
20
22
24
0 10 20 30
qT (MPa)
Dep
th (
m)
Sleeve Friction
0 200 400 600
fs (kPa)
Porewater Pressure
-100 0 100 200
u2 (kPa)
Shear Wave Velocity
0 100 200 300 400 500
Vs (m/s)
Vs
fs
u2
qt
u0
Ken Stokoe2004 Sowers
Lecture
In‐Situ QA/QC Testing for Dynamic Compaction
Hartsfield Airport Runway 5
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SCPTù at Atlanta Airport Runway 5
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
0 5 10 15 20
qT (MPa)
Dep
th (
m)
0 200 400 600
fs (kPa)
-100 0 100 200 300
ub (kPa)
0 100 200 300 400
Vs (m/s)t50 (seconds)
1 10 100 1000
Five Independent Readings of Soil Behavior: qt, fs, ub, t50, Vs
Equivalent Modulus for Static Loading
Gmax = t Vs2
t = t/g
Emax = 2Gmax(1+)
Modulus Reduction from Laboratory Data
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Mobilized Strength, /max or q/qmax
Mo
du
lus
Red
uct
ion
, G/G
max
or
E/E
max
NC S.L.B. Sand
OC S.L.B. Sand
Hamaoka Sand
Hamaoka Sand
Toyoura Sand e = 0.67
Toyoura Sand e = 0.83
Ham River Sand
Ticino Sand
Kentucky Clayey Sand
Kaolin
Kiyohoro Silty Clay
Pisa Clay
Fujinomori Clay
Pietrafitta Clay
Thanet Clay
London Clay
Vallericca Clay
= 1/FS
Open Dots = DrainedClosed Dots= Undrained
Resonant Column Torsional Shear Triaxial Shear with
local strain measurements
Modulus Reduction Scheme (Fahey & Carter 1993)
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Mobilized Stress Level, q/qmax
Mo
du
lus
Red
uct
ion
, E
/Em
ax
g = 1.0
g = 0.4
g = 0.3
g = 0.2
Note: f = 1
gqqfEE )/(1/ maxmax
= 1/FS
Equivalent Modulus for Static Monotonic Loading
• Initial Stiffness from Shear Wave Velocity (Vs)
Shear Modulus: Gmax = Vs2
Young's Modulus: Emax = 2 Gmax(1+) 0.20 at small strains
The proportion of load transferred from the top to base:
[3] Pb/Pt = x2/x3
The proportion of load carried in side shear is:
[4] Ps/Pt = 1 - Pb/Pt
The displacement at the pile toe/base is given by:
[5] wb = wt/cosh(L)
[6] = db/d = eta factor (Note: db = base diameter, so that = 1 for straight shaft piles)[7] = EsL/Eb = xi factor (Note: = 1 for floating pile; < 1 for end-bearing pile)[8] E = Esm/EsL = rho term. The parameter can be evaluated from: E = ½(1+Es0/EsL). [9] = 2(1+)Ep/EsL = lambda factor[10] = ln{[0.25 + (2.5 E(1- ) - 0.25)] (2L/d)} = zeta factor[11] L = 2(2/)0.5 (L/d) = mu factor
)cosh(
1
)1(
42 L
x
Es = Equivalent Elastic
Soil Modulus
AXIAL PILEDISPLACEMENTS
LengthL
Diameter dEso(surface)
EsM (mid-length)
EsL (along side at tip/toe/base)
Eb (base geomaterialModulus of layer 2)
sL
tt Ed
IPw
Pt Where Ip = displacementInfluence factor fromelastic continuum theory
O‐cell load tests in Piedmont rocksDrilled shafts ‐ Lawrenceville, GA (2011)
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Methods for Rating Rock Masses
Core Recovery (CR) Rock Quality Designation (RQD); Deere et al. (1966) Rock Mass Rating (RMR); Bieniawski (1976, 1989) Q‐System by NGI; Barton et al. (1976, 1991) Geological Strength Index (GSI); Hoek (1995, 2009)
Uniaxial Compressive Strength, qu Rock Quality Designation (RQD) Spacing of Joints Condition of joints and/or infilling Groundwater conditions
Rock Mass Rating (RMR)
Dick Goodman3rd Sowers
Lecture
Shear Wave Velocity Profile in Piedmont VC Summer Power Station, South Carolina