1 1 st st NORTH AMERICAN LANSLIDE CONFERENCE NORTH AMERICAN LANSLIDE CONFERENCE ROCK FALL SHEDS ROCK FALL SHEDS APPLICATION OF JAPANESE DESIGNS IN APPLICATION OF JAPANESE DESIGNS IN NORTH AMERICA NORTH AMERICA June 5, 2007 June 5, 2007 Dr. H. Yoshida Dr. H. Yoshida Toshimitsu Nomura Toshimitsu Nomura Duncan C. Wyllie Duncan C. Wyllie Anthony J. Morris Anthony J. Morris Kanazawa University, Kanazawa, Japan Kanazawa University, Kanazawa, Japan Protec Engineering, Niigata, Japan Protec Engineering, Niigata, Japan Wyllie & Norrish Rock Engineers, Vancouver, Canada Wyllie & Norrish Rock Engineers, Vancouver, Canada Canadian Pacific Railway, Calgary, Canada Canadian Pacific Railway, Calgary, Canada
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11stst NORTH AMERICAN LANSLIDE CONFERENCENORTH AMERICAN LANSLIDE CONFERENCE
ROCK FALL SHEDSROCK FALL SHEDSAPPLICATION OF JAPANESE DESIGNS IN APPLICATION OF JAPANESE DESIGNS IN
NORTH AMERICANORTH AMERICAJune 5, 2007June 5, 2007
Dr. H. YoshidaDr. H. YoshidaToshimitsu NomuraToshimitsu Nomura
Duncan C. WyllieDuncan C. WyllieAnthony J. MorrisAnthony J. Morris
1.1. Rock fall sheds in JapanRock fall sheds in Japan2.2. Rock fall analysisRock fall analysis3.3. Principles of rock shed design and testingPrinciples of rock shed design and testing4.4. Design impact energies and forcesDesign impact energies and forces5.5. North American rock fall sheds:North American rock fall sheds:
Kicking Horse Canyon Shed, CanadaKicking Horse Canyon Shed, CanadaPitkins Curve Shed, CAPitkins Curve Shed, CAFerguson Rock Slide Shed, CAFerguson Rock Slide Shed, CA
ROCK FALL MITIGATION STUDYNIIGATA AND KANAZAWA
JAPAN
OCTOBER 20 TO 25, 2003
Niigata
To Tokyo
Kanazawa
Sea of Japan
Rock Sheds
Fence “Rock Keeper”
Concrete Barrier
Rock Shed
MSE Barrier
Sand Cushion
Styrofoam
5 10 20 50 100 200 300 500 1000
Rel
ativ
e C
onst
ruct
ion
Cos
t
5
10
5
0
100
2
00
500
Impact Energy Capacity (tf.m)
Styrofoam cushionSand
cushionSuper shed
SHEDSSHEDSRock Shed
Pre-cast concrete shed
“Super Rock Shed” – high ductility shed, capacity 800 tf m
Test loading:Mass = 44,000 lbHeight = 120 ft.
Summary of TopicsSummary of Topics
1.1. Rock fall sheds in JapanRock fall sheds in Japan2.2. Rock Rock fallfall analysisanalysis3.3. Principles of rock shed design and testingPrinciples of rock shed design and testing4.4. Design impact energies and forcesDesign impact energies and forces5.5. North American rock fall sheds:North American rock fall sheds:
Kicking Horse Canyon Shed, CanadaKicking Horse Canyon Shed, CanadaPitkins Curve Shed, CAPitkins Curve Shed, CAFerguson Rock Slide Shed, CAFerguson Rock Slide Shed, CA
Rock fall modeling programsRock fall modeling programs
Objective of modeling is to determine:Objective of modeling is to determine:Velocity of rock falls, which is used to determine impact Velocity of rock falls, which is used to determine impact energy on protection structureenergy on protection structureTrajectory of rock falls to determine dimensions of Trajectory of rock falls to determine dimensions of protection structure protection structure
Energy Loss during Rock FallsEnergy Loss during Rock Falls
⎟⎟⎠
⎞⎜⎜⎝
⎛−⋅⋅=
ftanHgV
ψμ12
ψf
μ – friction coefficient at impact points
HgV ⋅⋅= 20
Free fall velocity:
Fall velocity, V
Rock fall velocitiesRock fall velocities
0
50
100
150
200
250
0 10 20 30 40 50 60 7
V e lo c it y (m/s)
Free fall velocity
Bare rock faces:Slope = 45°μ = 0.40 (impact)
Talus slopes:Slope = 31°μ = 0.35 (rolling)
Rock fall velocity, V (m/s)
Fall
heig
ht, H
(m)
Energy loss due to impacts
on slope
Skagway
Swiss test
Big Sur
Term
inal
vel
ocity
?
⎟⎟⎠
⎞⎜⎜⎝
⎛−⋅⋅=
ftanHgV
ψμ12
Summary of TopicsSummary of Topics
1.1. Rock fall sheds in JapanRock fall sheds in Japan2.2. Rock fall analysisRock fall analysis3.3. Principles of rock shed design Principles of rock shed design
and testingand testing4.4. Design impact energies and forcesDesign impact energies and forces5.5. North American rock fall sheds:North American rock fall sheds:
Kicking Horse Canyon Shed, CanadaKicking Horse Canyon Shed, CanadaPitkins Curve Shed, CAPitkins Curve Shed, CAFerguson Rock Slide Shed, CAFerguson Rock Slide Shed, CA
Weight impact force –mass x deceleration
Rock mass
Transmitted force distribution
Cushion material
Rock shed roof
Transfer of impact energy into shed structureTransfer of impact energy into shed structure
Weight impact force –mass x deceleration
Transmission impact force –integration of transmitted
pressure on distributed area
Cushion material
Instrumented shed to measure weight impact and transmission impact forces
W = 10kN
Span length
12m10m8m
0 5 10 15 200
2
00
400
60
0
Fall Height (m)M
axim
um re
actio
n fo
rce
(kN
)
Test Setup (plan view)
Load cell(Unit: mm)
2H-390X300X10X16 (Base beam)
Beam A
Beam B
250
Sand Tank
3175
Span length
Displacement meter
Earth pressure gauge
650
170
150 2H-390X300X10X16 (Main beam)
250
Test Setup (plan view)
Load cell(Unit: mm)
2H-390X300X10X16 (Base beam)
Beam A
Beam B
250
Sand Tank
3175
Span length
Displacement meter
Earth pressure gauge
650
170
150 2H-390X300X10X16 (Main beam)
250
Variation of weight and transmission impact forces with
time, full-scale tests
Span length (m)
Deformation
Styrofoam
Sand
Rubber tires
Forc
eRelationship between
force and deformation for three cushioning materials
Deformation
Pre-cast concrete shed
Hinge in column
Rigid connection between column and roof beam
Longitudinal connection between roof beams
Pinned connection
Hinge at base of column
Column
Roof beam
Post tensioned
cables
Rigid connection
between roof beams and
columns
Post tensioned cables joining
roof slabs
Summary of TopicsSummary of Topics
1.1. Rock fall sheds in JapanRock fall sheds in Japan2.2. Rock fall modelingRock fall modeling3.3. Principles of rock shed design and testingPrinciples of rock shed design and testing4.4. Design impact energies and Design impact energies and
forcesforces5.5. North American rock fall sheds:North American rock fall sheds:
Kicking Horse Canyon Shed, CanadaKicking Horse Canyon Shed, CanadaPitkins Curve Shed, CAPitkins Curve Shed, CAFerguson Rock Slide Shed, CAFerguson Rock Slide Shed, CA
Design Impact Load, Design Impact Load, PP
15352321082 −= βλ /// H)mg(.P
Japanese Rock Fall Protection Measures Handbook (2000)Japanese Rock Fall Protection Measures Handbook (2000)
m = rock fall mass (tonnes)λ = Lame constant, 1000 kNm-2 for soft sand cushioning material H = fall height, mβ = factor defining the relationship between the thickness of cushioning layer (T, m) and the diameter of the impacting rock (D, m)
580.
DT −
⎟⎠⎞
⎜⎝⎛=β
Relationship Cushion Thickness (T), Rock Fall Dimension (D) and Factor β
ββ
T/D
Large value for T adds
weight with little increase
in energy absorption
Distribution of impact load through Distribution of impact load through cushion on to roof of shedcushion on to roof of shed
Sand cushion, thickness T
Effective area of transmitted force on
roof, A
4
2TA π=
Roof
Summary of TopicsSummary of Topics
1.1. Rock fall sheds in JapanRock fall sheds in Japan2.2. Rock fall analysisRock fall analysis3.3. Principles of rock shed design and testingPrinciples of rock shed design and testing4.4. Design impact energies and forcesDesign impact energies and forces5.5. North American rock fall sheds:North American rock fall sheds:
Kicking Horse Canyon Shed, Kicking Horse Canyon Shed, CanadaCanadaPitkins Curve Shed, CAPitkins Curve Shed, CAFerguson Rock Slide Shed, CAFerguson Rock Slide Shed, CA
Kicking Horse Canyon
Rock falls are concentrated in gulliesRock falls are concentrated in gullies
Rock shed location19 m
Clearance envelope
“Crash” wall with socket connection to column
Column (pre-cast)
with flexible hinge
Granular fill Rock anchor
with tie-back through wall
Sand cushion 900 mm thick
Rigid connection – post-tensioned cables
Footing supported with rock socketed
pilesRock fill
supporting track
Roof beams (pre-cast) with ducts for longitudinal
connection cables
Retaining wall (cast in place)
Footing dowelled to
rock foundation
Pinned connection with rubber pad
Clearance envelope
Top of “crash” wall with sockets for lower ends of
columns.
Valley-side
columns, 1500 O.C.
Concrete blocks to
retain sand
cushion
Elevation view
Roof beams
Summary of TopicsSummary of Topics
1.1. Rock fall sheds in JapanRock fall sheds in Japan2.2. Rock fall analysisRock fall analysis3.3. Principles of rock shed design and testingPrinciples of rock shed design and testing4.4. Design impact energies and forcesDesign impact energies and forces5.5. North American rock fall sheds:North American rock fall sheds:
Pitkins Curve Shed, CAPitkins Curve Shed, CAFerguson Rock Slide Shed, CAFerguson Rock Slide Shed, CA
Pitkins Curve, Highway 1, CAPitkins Curve, Highway 1, CA
Pitkins Curve Shed• 45 m high rock face• Design rock fall ~2.5 m
Artists rendering of completed project
Roof protection –Styrofoam with sand covering
Widely spaced columns to maximize view of ocean
Summary of TopicsSummary of Topics
1.1. Rock fall sheds in JapanRock fall sheds in Japan2.2. Rock fall modelingRock fall modeling3.3. Principles of rock shed design and testingPrinciples of rock shed design and testing4.4. Design impact energies and forcesDesign impact energies and forces5.5. North American rock fall sheds:North American rock fall sheds: