(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)
- d) An oedometer test was also performed on a (saturated) reconstituted sample obtained at the site. The initial void ratio was calculated as 1.005 and the initial sample height was 20 mm. The following measurements were reported for each of the 24-hr stress increments: Table 4. Oedometer test measurements Normal stress (kPa) 1.5 13 26 52 104 208 416 Change in sample height (mm) 0.419 0.199 0.229 0.209 0.208 0.199 Plot the evolution of the void ratio resulting from the data above using semi-logarithmic axes (i.e. produce an e-log o'y plot). Is there anything you can comment on the stress history and consolidation state of the soil?arrow_forwardFind the angle of internal friction for the sand specimen, if the deviator stress at failure is 100kPa, the cell pressure is 50kPa.if the sample is a dry sand specimen put through a triaxial test. A 30' в 15° C 45' D 37'arrow_forwardIf the two temperature readings of softening point test are (50.0 and 50.5)°C, the softening point of the specimen *arrow_forward
- 3. In a drained tri-axial test, a specimen is confined under pressure and axially loaded until failure. The failure conditions of the specimen are analyzed for shear strength. What is the value of the minor principle stress? Half the value of the major principle stress Twice the value of the major principle stress . The same as the confining pressure The same as the cohesion value ● ● ●arrow_forwardA very long steel drill pipe got stuck in hard clay at an unknown depth. The drill pipe was applied a large upward force and observed that the drill pipe came out elastically by 500 mm. It was also observed that there was elongation of 0.04 mm in a gauge length of 200 mm. Estimate the depth of hard clay bed. Following consideration may be taken into account: Resistance offered by all material/elements may be taken as zero.arrow_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
- On close investigation of a sample it was found to be in three layers 20mm, 60mm, and 40mm. The permeability of these layers are 3x10-³mm/sec, 5x10-4mm/sec, and 17x10-4mm/sec respectively. Find kH kyi H, +kµz ·H, +kµ3 H; +…+ k, · H, Harrow_forwardIn 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 |arrow_forwarda) Following results are obtained in a series of CU triaxial tests on saturated samples of a clay. Calculate the effective shear strength parameters (c' and ') and plotting the Mohr- Coulomb failure envelope. (Hint: you can first plot the top points of the circles in q=(01-03)/2 vs. p=(₁03)/2 space.) Test number Confining (cell) Pressure (kPa) Deviator stress (01-03) (kPa) Pore pressure before shear (kPa) Pore water pressure at failure (kPa) ● 1 400 120 300 320 2 400 210 200 260 3 550 270 250 235 b) If we carry out a consolidated drained triaxial test on a specimen taken from the same clay (assume same c', '), what would be the deviator force at failure in a specimen that is consolidated under an isotropic stress of 240 kPa and pore pressure of 300 kPa. The specimen was initially 5 cm in diameter and 10 cm in height. Peak strength (i.e. failure) is reached at axial strain of 4% and volumetric strain of 2% in compression. Hints: the pore pressure is initial pore water pressurearrow_forward
- The penetration value of a bitumen sample tested at 25°C is 80. When this sample is heated to 60°C and tested again, the needle of the penetration test apparatus penetrates the bitumen sample by d mm. The value of d CANNOT be less than mm.arrow_forwardAn intact rock sample was subjected to triaxial testing, and the results of the tests are given below. When repeating the test at 15.0 MPa confinement, the jacket punctured, and the pore pressure built up to a value equal to the confining pressure during the test. What would be the peak axial stress? Confining pressure Axial stress at failure [MPa] [MPa] 03 (MPa) а1 (MPa) 0.0 74.0 5.0 85.0 10.0 95.0 15.0 115.0 O a. 94.5 MPa O b. 105.0 MPa O c. 115.0 MPa O d. 92.0 MPa O e. 89.0 MPaarrow_forward4. Given the following data: the porosity obtained from this method is the effective porosity,. Weight of the clean dried core sample in air: Wtdry = 20.0 gm Weight of the core sample saturated with water: Wtsat = 22.5 gm . Density of water: pw = 1.09m CC what is the pore volume of the sample?arrow_forward
- Fundamentals of Geotechnical Engineering (MindTap...Civil EngineeringISBN:9781305635180Author:Braja M. Das, Nagaratnam SivakuganPublisher:Cengage Learning