shear strength lab
TRANSCRIPT
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Applications of Strength Analysis
Earth Slopes
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Applications of Strength Analysis
Structural Foundations
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Applications of Strength Analysis
Retaining Wall
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Applications of Strength Analysis
Tunnel Linings
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Applications of Strength Analysis
Pavement Design
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Direct Shear Test
Pavement Design
Shear Box &Specimen Ring
ShearLoad
Normal
LoadTest Control
&Data
Acquisition
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N Normal Load
T
Shear Load
Internal Diameter
Plan area, A = x r
2
Normal stress,n= N/ A
Shear stress, = T/ A
Shear Box Schematic
Reaction Arm
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Shear Stress vs. Horizontal Displacement (Strain)
0
10
20
30
40
50
60
70
0 0.05 0.1 0.15 0.2 0.25 0.3
ShearStress(psi)
Horizontal Displacement (in)
10 psi
50 psi
90 psi
Peak Strength
Residual Strength
Dense Sand
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0
10
20
30
40
50
60
70
80
0 10 20 30 40 50 60 70 80 90 100
(
psi)
(psi)
Peak Residual Linear (Peak) Linear (Residual)
r
p
Shear Stress vs. Normal Stress (Peak & Residual)
Dense Sand
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0
10
20
30
40
50
60
70
80
0 10 20 30 40 50 60 70 80 90 100
(
psi)
(psi)
Peak Linear (Peak)
Mohrs Circle
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H vs. Horizontal Displacement (Strain)
y
x
Dense sands
Loose sands
any behaviour
in between
Contraction
Dilation
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-0.035
-0.03
-0.025
-0.02
-0.015
-0.01
-0.005
7E-17
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0 0.05 0.1 0.15 0.2 0.25 0.3
H
(in)
Horizontal Displacement (in)
10 psi
50 psi
90 psi
H vs. Horizontal Displacement (Strain)
Contraction
Dilation
Dense Sand
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Void Ratio(e) vs. Horizontal Displacement (Strain)
Initially Loose Soil
Initially Dense Soil
Critical
Void RatioVoidRatio,e
H V d eCalculation Steps
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Index of Required Plots
Shear Stress vs. Horizontal Displacement
Shear Stress vs. Normal Stress (Peak & Residual)
Mohrs Circle (Peak Only)
H vs. Horizontal Displacement
Void Ratio (e) vs. Horizontal Displacement
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Grain Shape &
Holtz & Kovacs
Rounded 30 - 35o
Sub-angular 34-39o Angular 36-41o
Sub-rounded 32 - 37o
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Tips
Post PROCESSED data (not raw) data on blackboard group shear strength ofsand/glass by end of tomorrow.
Note the spot on the blackboard is : CIE 337 Merged Fall 2012==>>LabGroups===> Direct Shear.===> File Exchange
The completed table at the end of the manual of Lab 7 (Page 72) should also
be uploaded. Please put all in ONE file Plot your own data alongside data from ONE other group that used the other
material. You are comparing the shear strength of Ottawa Sand vs crushedglass.
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Lab Procedure Key Points
Fill & levelsand tobottom ofmarking inspecimen box
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Lab Terminology
SpecimenBox
Spacer TopCap
LoadSeat
PorousStone
ReactionArm