(a)
State whether the statement “thinner the wall, the higher is the area ratio of a sampling tube” is true or false.
(a)
Answer to Problem 12.1P
The given statement is
Explanation of Solution
Show the expression for the area ratio.
Here,
As per the formula, the area has the direct proportional relationship with the value of
The formula denotes if the wall thickness of the sampling tube is high, the area ratio will be higher and vice versa.
Hence, the given statement is
(b)
State whether the statement “samples recovered from the split-spoon samplers are highly disturbed” is true or false.
(b)
Answer to Problem 12.1P
The given statement is
Explanation of Solution
Split-spoon samplers are used to obtain representative samples suitable for the field examination of soil texture and fabric. The samples obtained by this process are highly disturbed.
Hence, the given statement is
(c)
State whether the statement “
(c)
Answer to Problem 12.1P
The given statement is
Explanation of Solution
Express the relationship between standard penetration numbers
In
Thus, the value of
Hence, the given statement is
(d)
State whether the statement “
(d)
Answer to Problem 12.1P
The given statement is
Explanation of Solution
Express the relationship between the effective overburden pressure
Here,
The value of
The value of
The value of
Hence, the given statement is
(e)
State whether the statement “vane shear test can be carried out in sands” is true or false.
(e)
Answer to Problem 12.1P
The given statement is
Explanation of Solution
The un-drained shear strength of soft clay is estimated directly by the Vane shear test. Reliable results only in medium stiff clays and soft clays are obtained from the field vane shear test.
Vane shear test is valid for only cohesive soil and it is not suitable for clays which contain sand or silt laminations in it.
Hence, the given statement is
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Chapter 12 Solutions
Fundamentals of Geotechnical Engineering (MindTap Course List)
- A standard penetration test is carried out in sand where the efficiency of the hammer nH =70%. If the measured N-value at 30 ft depth is 24, find N60 and (N1)60. The unit weight of the sand is 115.0 lb/ft3. Assume nB = nS = nR =1.arrow_forwardThe unconfined compression test sampler is : Split Spoon sampler Sonotube sampler Shelby tube samplerarrow_forwardA soil sample is consolidated in the triaxial chamber under a chamber pressure of 200 kN/m2. The drain valve closes and the sample fails by applying the diverter stress Calculate the value of:-The sample breakage diverter value-The pore pressure value at the moment the specimen breaks- Skempton's A parameterThe soil shear strength parameters are: c=0, ϕ=14° and c'=0, ϕ=20°arrow_forward
- A direct shear test is performed on a specimen of dry sand. The shear box is circular in cross-section with a diameter of 50 mm. The normal force imposed on the specimen is 250 N. Then shears when the shear force is 150 N. Determine the angle of internal friction of this sand.arrow_forwardCan TRIAXIAL TESTS be performed on sand samples? Briefly explain. The results of an undrained triaxial test on a clay soil sample are given in table below Cell Pressure (kN/m2) 200 400 600 Additional Axial Load at Failure (N) 342 388 465 Each sample, originally 76mm long and 38mm in diameter, experienced a vertical deformation of 5.1mm. Evaluate the stress at failure for each cell pressure given in table above. Draw Mohr Circles and determine the shear strength parameters of the soil.arrow_forwardA series of previous CD tests conducted on a NC clay has established that the ultimate effective friction angle of the clay is 300. Now a CU test is conducted on this soil with an effective cell pressure of 100 kPa. The specimen fails at a deviatoric stress of 100 kPa. Estimate the pore pressure at failure. Given: σ3f′=Kaσ1f′whereKa=1−sinϕ1+sinϕ Please do fast .... ASAP Fastarrow_forward
- 2. 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_forwardThe results shown in the following table were obtained at the peak in a series of CU tests with constant cell pressure (isotropic) for a given soil. Cell Pressure (σc, kPa) Axial Stress at Failure (σd, kPa) Pore Pressure (Δu, kPa) 100 260 30 200 450 60 a) draw the effective stress path using p-q diagram of each test. b) draw s-t stress paths (effective) and determine the shear strength parametres (Φ', c') using Kf - line.arrow_forwardThe 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_forward
- There is an upward flow of 0.06 ml/s through a sand sample with a coefficient of permeability 3 × 10^–2 mm/s. The thickness of the sample is 150 mm and the cross-sectional area is 4500 mm2.Determine the effective stress in N/m2 at the bottom the sample, if the saturated unit weight of the sample, is 18.9 kN/m3. Provide Diagram a.709.5 b.177.38 c.88.69 d.354.75arrow_forwardPlease briefly explain the Mohr-Coulomb Failure Criterionarrow_forwardA triaxial test was performed on a dry. cohesionless sand. The sample fails when the confining stress (minor principal) is 45 kPa and the axial stress (major principal) is 89 kPa. Determine the angle of internal friction Φ for the soil. Adjust your answer to TWO decimal places.arrow_forward
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