Concept explainers
(a)
State whether the statement “drilled shafts also include large diameter driven piles” is true or false.
(a)
Answer to Problem 19.1P
The given statement is
Explanation of Solution
The drilled shafts are cylindrical and deep; cast-in-place concrete foundations are poured in these shafts and by drilling process; whereas driven piles are commonly driven into the ground in situ.
Hence, the drilled shafts do not include large diameter of driven piles.
Therefore, the given statement is
(b)
State whether the statement “drilled shafts can be 500 mm in diameter” is true or false.
(b)
Answer to Problem 19.1P
The given statement is
Explanation of Solution
The drilled shaft diameter can range from 2 ft (609.6 mm) to 30 feet (9,144 mm). Thus, the drilled shafts cannot be in diameter of 500 mm.
Therefore, the given statement is
(c)
State whether the statement “adhesion factor
(c)
Answer to Problem 19.1P
The given statement is
Explanation of Solution
The adhesion factor for stiff clays can range from 0.3 to 0.45, and the larger value of adhesion factor is used for soft clay due to its more unit skin friction.
Therefore, the given statement is
(d)
State whether “drilled shafts in sands derive most of their load carrying capacity from the point resistance than the skin friction” is true or false.
(d)
Answer to Problem 19.1P
The given statement is
Explanation of Solution
The drilled shafts’ capacity is developed from the combination of end bearing and side shear. The side shear is correlated to the soil shear strength and in sands, the friction is less.
Therefore, the given statement is
(e)
State whether the statement “when the settlement is 1% of the drilled shaft diameter, greater fraction of skin friction is mobilized than the point load in sands and clays” is true or false.
(e)
Answer to Problem 19.1P
The given statement is
Explanation of Solution
The arrangement of sands and clays was done during the initial drilling process rather than the end point. When 1% of settlement is achieved, the soil which is around the shaft gets mobilized much earlier than the end point.
Therefore, the given statement is
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Chapter 19 Solutions
Fundamentals of Geotechnical Engineering (MindTap Course List)
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- 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_forwarda. 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. Determine the undrained shear strength of the clay. b. The clay soil described in part (a) has a liquid limit of 58 and a plastic limit of 29. What would be the corrected undrained shear strength of the clay for design purposes? Use Bjerrum’s relationship for λarrow_forwardTake o, = 580 kPa (Figure 1) Express your answer to three significant figures and include the appropriate units. HÀ ? o, = Value Units Submit Request Answer Figure Part B Determine the shear stress acting on the inclined plane AB. Express your answer to three significant figures and include the appropriate units. В HA ? 30° Value Units Aarrow_forward
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- Find active thurst P₁ = ? when tension crack has not yet appeared A B 2 m 3 m C 2 Clay Y₁ = 17 kN/m² 2 c=15 kN/m² $₁ = 20° 3 1₂= 16 kN/m c = 0 (Sand) $₂ = 20°arrow_forwardA sample of sand is sheared in the following manner. First an all around normal stresso 350 kPa is applied to the sample. Next a shear stress is applied to the horizontal pia while the normal stress remains constant. The shear stresses at failure are + 186 kPa. Ihe initial stress and stress condition at failure are shown below 350 kPa 350 kPa 186 kPa 350 kPa 350 kPa ー550 kPa 550 kPa 186 kPa 350 kPa 350 kPa Initial Conditions At Failure Determine the Following: fo A) Assuming c, = 0, draw a failure envelope for the soil. Define the friction angle ( the soil. B) Draw the Mohr's Circle at failure for the test. C) Show the location of the pole. D) Define the maximum and minimum principal stresses at failure. E) Define the normal stress corresponding to the maximum shear stressarrow_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_forward
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