Q6): The effective shear strength equation of a saturated clayey soil can be as S=25+ o tan 30. In undrained test on a sample of the same soil using the Shear box apparatus the following data at failure were recorded: shear Stress=90 kPa and normal stress = 180 kPa. a): what was the pore water pressure in the specimen at the time of failure? b): Find the undrained compressive strength for the same soil when tested in unconfined compression test. c): Find the major principal stress when tested in UU test with confining pressure of 200 kPa.

Q6): The effective shear strength equation of a saturated clayey soil can be as S=25+ o tan 30. In undrained test on a sample of the same soil using the Shear box apparatus the following data at failure were recorded: shear Stress=90 kPa and normal stress = 180 kPa. a): what was the pore water pressure in the specimen at the time of failure? b): Find the undrained compressive strength for the same soil when tested in unconfined compression test. c): Find the major principal stress when tested in UU test with confining pressure of 200 kPa.

Fundamentals of Geotechnical Engineering (MindTap Course List)

5th Edition

ISBN:9781305635180

Author:Braja M. Das, Nagaratnam Sivakugan

Publisher:Braja M. Das, Nagaratnam Sivakugan

Chapter10: Shear Strength Of Soil

Section: Chapter Questions

Problem 10.10P

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A direct shear test was conducted on a dried sand sample in a test box of 60mm x 60mm normal load of 400N. The soil sample failed at an applied shear force of 250N. a. Determine the shear strength parameters of the soil. b. Estimate the required shear force to cause a shear failure under a normal load of 600N. (Show all working calculations.)
Question Table 1 gives data from a standard shearbox(direct shear) test on a sample of 125g of dry sand. The initial dimensions of the sample were 60mmx60mm on plan x20mm in height. The test was caried out at a constant normal effective stress of 50k:Pa. Take the specific gravity of the soil grains Gs=2.65. Plot graphs of (a) shear stress t against shear strain y; (b) volumetric strain evol against shear strain y; (c) specific vohume v against shear strain y. (d) Comment on these graphs and estimate the peak and critical state effective angles of friction of the soil. Table 1: Shearbox Data Relative horizontal Upward vertical movement Shear stress t (kPa) displacement x (mm) of shearbox lid y (mm) 0.00 0.000 0.02 0.002 19 0.04 0.008 34 0.06 0.016 43- 0.08 0.026 47 0.20 0.064 56 0.32 0.128 51 0.48 0.192 46 0.64 0.256 41 0.80 0.288 37 0.96 0.320 34 1.12 0.321 33
Two undrained triaxial tests were conducted on soil specimen, and they gave the following results: Sample Confining Pressure Deviator Stress A 350 kN/m² B 500 kN/m² 150 kN/m² 300 kN/m² The shear strength of sample A in the plane of it's normal stress is A 588 kPa B 283 kPa C 730 kPa D 165 kPa Correct Option
x 18 The effective shear strength equation (S = T₁ = 25+5 tam 30); expressed for a saturated clayey soil. In undrained test on a sample of the same soil using the shear box apparatus, the following data at failure were recorded :. Shear Stress = 90 kPa a) What and Normal stress = 180 kPa pore water pressure in the specimen at time of was the failure (assume Øu= 0). Find the Unconfined compressive strength (Od max) for the same soil an Unconfined. when tested in Compression test. c) Find the major principal stress when a sample of the same soil is tested in Ul test with confining pressure of (200 kPa).
Using a deviator stress vs axial strain diagram, explain how the failure stress increases with cell pressure in a triaxial test. (i) Shear strength of a cohesive soil was determined in the laboratory using two samples. The first sample failed at a shear stress of 83 kPa and an effective normal stress of 90 kPa. The second sampled failed at 107 kPa and 135 kPa respectively. Determine the shear strength parameters (ii) of the soil.
Table 1 gives data from a standard shearbox(direct shear) test on a sample of 125g of dry sand. The initial dimensions of the sample were 60mmx60mm on plan x20mm in height. The test was camried out at a constant normal effective stress of 50kPa. Take the specific gravity of the soil grains Gs=2.65. Plot graphs of (a) shear stress r against shear strain y; (b) volumetric strain evol against shear strain y; (c) specific volume v against shear strain y. (d) Comment on these graphs and estimate the peak and critical state effective angles of friction of the soil. Table 1: Shearbox Data Relative horizontal displacement x (mm) of shearbox lid y (mm) Upward vertical movement Shear stress t (kPa) 0.00 0.000 0.02 0.002 19 0.04 0.008 34 0.06 0.016 43- 0.08 0.026 47 0.20 0.064 56 0.32 0.128 51 0.48 0.192 46 0.64 0.256 41 0.80 0.288 37 0.96 0.320 34 1.12 0.321 33
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A triaxial compression test was conducted on a saturated soil sample to determine its shear strength parameters: effective cohesion (C') and effective friction angle (O'). The confining pressure used during the test was 30 psi. The deviator stress on the sample at the time of failure was 40 psi. The porewater pressure measured at the time of failure was 5 psi a) The figure below shows the stress conditions on the sample at the time of failure. Provide the values of total stresses, o1 and oz on the sample. Total horizontal stress, o3 (psi) = (Report to the nearest whole number, i.e. no decimals) Total vertical stress, o1 (psi) (Report to the nearest whole number, i.e. no decimals) %3D b) The figure below shows the effective stress Mohr's Circle for the above soil sample at failure. What are the values of effective normal stresses at points A and B?
A series of direct shear tests were conducted on a sample of soil in a 60 mm square shear box. The table below shows the results that were obtained at failure. Plot the graph of shear stress at failure against normal stress anddetermine the strength parameters of the soil. Normal Load (N) 200 300 400 Shear Load (N) 105 142 180
The direct shear test was performed for three soil specimens, it gave the following observations: Specimen No. 1 2 3 Normal Stress (kN/m²) 70 150 225 Shear Stress at failure (kN/m²) 55 87.5 117.9 1- Find the strength parameters (c and Ø) 2- The angle of failure plane (0) 3- Find the principles stresses for specimen (No. 2)
In Triaxial test, which of the following parameters do not need to be recorded the confining pressure specimen diameter changes ) the generated pore pressure the axial force A Triaxial test was performed on a dry, cohesionless soil. If the sample failed vhen the minor principal stress was half of the major principal stress, the soil's angle of internal friction is: O 22.5 19.5 33.3 O 25 A technician obtained a soil void ratio of 1.5. It is okay because it is possible to measure void ratio values above 1. True False |