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A series of vane shear tests have been performed on a soft clay stratum. The results of these tests are as follows:
The vane was 60 mm in diameter and 120 mm long. The soil has a liquid limit of 100 and a plastic limit of 30. Compute the undrained shear strength for each test, then develop a plot of undrained shear strength versus depth. This plot should have depth on the vertical axis, with zero at the top of the plot.
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- Q-4: Soil samples have been collected from a virgin ground and sent to a NATA accredited laboratory to determine shear strength parameters. The laboratory conducted direct shear test using 100 mm X 100 mm samples and returned the following test result. Test no. 1 2 Normal stress (kPa) 100 200 Shear stress at failure (kPa) 77.74 135.47 For the given soil, determine minor principal stress when major principal stress is are 450 kPa.arrow_forward2. A series of consolidated, undrained triaxial tests were carried out on specimens of a saturated clay under no backpressure. The test data at failure are summarized: Confining Pressure (kPa) Deviator Stress (kPa) Pore Water Pressure (kPa) 150 192 80 300 341 154 450 504 222 a. Draw the Mohr circles and find the cohesion and friction angles in terms of effective stresses. b. Compute Skempton’s A-parameter at failure for all three specimens. c. Is the soil normally consolidated or overconsolidated? Why? d. Another specimen of the same clay that was consolidated under a cell pressure of 250 kPa was subjected to a consolidated, drained triaxial test. What would be the deviator stress at failure?arrow_forward24.A series of consolidated, undrained triaxial tests were carried out on specimens of asaturated clay under no backpressure. The test data at failure are summarized:Confiningpressure (kPa) Deviator stress(kPa) Pore waterpressure (kPa) 150 192 80300 341 154450 504 222 a. Draw the Mohr circles and find the cohesion and friction angles in terms of effectivestresses.b. Compute Skempton’s A- parameter at failure for all three specimens.c. Is the soil normally consolidated or over consolidated? Why?d. Another specimen of the same day that was consolidated under a cell pressure of 250 kPa wassubjected to a consolidated, drained tri axial test. What would be the deviator stress at failure?arrow_forward
- The table shows the results of a consolidated undrained (CU) test on a overconsolidated clay soil sample. Sample No Cell Pressure (kPa) Deviator stress at failure (kPa) Pore water pressure at failure (kPa) 1 15 20 10 2 30 25 15 For the given data, plot the effective stress Mohr's circles at failure. Estimate the effective shear strength parameters C' amd phi'.arrow_forwardProblem 2: The following data were obtained in a direct shear test. ... 20 kPa Normal pressure .... Tangential Pressure Cohesion of soil 15 kPa 8 kPa Determine the following: a) Angle of internal friction, ø b) Compute the angle that the failure plane makes with the horizontal, 0. c) Compute the minimum principal stress. d) Compute the max. principal stressarrow_forwardA triaxial test conducted on cohesionless soil gives the following results: Deviator stress at failure = 410kPa The angle of shearing resistance = 32 degrees Determine the following: a. Confining pressure in kPa b. Shear stress at failure plane in kPa c. Angle that the failure plane makes with the principal plane (degrees)arrow_forward
- A vane shear test was conducted in a saturated clay. The height and diameter of the rectangular vane were 4 in. and 2 in., respectively. During the test, the maximum torque applied was 230 lb-in. The clay soil has a undrained shear strength of 7.844 psi. It has a liquid limi of 58 and a plasic limi o 29. What would be the corrected undrained shear strength of the clay for design purposes? Using Bjerum's relationship for λ. λ = 1.7 - 0.54 log[PI(%)]arrow_forwardLaboratory tests to determine shear strength parameters generally consists of direct shear and triaxial tests. Table 1 present data obtained from consolidated-undrained tests on a soft clay. Table 1: Triaxial test results At failure Pore water pressure (kN/m²) Cell pressure (kN/m²) Cu 200 400 800 Deviator stress (kN/m²) 117 242 468 110 227 455 Determine the shear strength parameters in terms of effective stress 3 90 ap uu im Cu to 207 415arrow_forwardA sample of dry sand is tested in direct shear. Theshear box holding the sample has a circular crosssection with a diameter of 50 mm. The normal(compressive) load imposed is 200 N. The sam-ple shears when the shear force is 130 N.(a) Determine the test normal stress and shearstress at failure.(b) Determine the angle of internal frictionfor this soil.(c) What is the probable condition of the testedsample (dense, loose, etc.)?arrow_forward
- A vane shear test was performed on saturated clay layer at the site and it is noted that a torque of 45 N-m was required to shear the soil. In order to remould the soil, the vane was rotated rapidly under the certain value of torque say "x". If the sensitivity of the clay is 8, then calculate the value of "x" in N-m. Assume diameter and length of the vane to be 70 mm and 130 mm respectively, consider two way shearing,arrow_forwardA sand sample was used in a direct shear test for two trials. The first trial obtained a normal stress of 4000 psf when the shear stress at failure is 3000 psf. For the second trial, the normal stress is 6000 psf when shear stress at failure is 4000 psf. • Determine the angle of internal friction• Determine the value of apparent cohesion• Shear stress 15ft beneath the surface (psf) if the soil unit weight is 150 pcf• Major and minor principal stresses (psf)Final answer(s) should be in 3 decimal places.arrow_forward1. Test A set of 4-in diameter direct shear tests were conducted on a lightly cemented sand. Test results are as shown. Plot the data (units = psf) and determine c' (in psf) and '. How would c' change if there were no cementation? Number 1 2 3 Forces At Failure Normal (lb) 60 120 180 Shearing (lb) 40 71 108 Shear Stresses at Failure Normal (psf) Shearing (psf) 688 458 1375 814 2063 1238 c' = c' = 29.5 degrees 57.3 psf 0.4 psiarrow_forward
- Principles of Foundation Engineering (MindTap Cou...Civil EngineeringISBN:9781337705028Author:Braja M. Das, Nagaratnam SivakuganPublisher:Cengage LearningPrinciples of Geotechnical Engineering (MindTap C...Civil EngineeringISBN:9781305970939Author:Braja M. Das, Khaled SobhanPublisher:Cengage Learning