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(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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- For the drilled shaft described in Problem 19.7, estimate the total elastic settlement at working load. Use Eqs. (18.45), (18.47), and (18.48). Assume that Ep = 20 106 kN/m2, s = 0.3, Es = 12 103 kN/m2, = 0.65 and Cp = 0.03. Assume 80% mobilization of skin resistance at working load. (See Part c of Problem 19.7) 19.7 Figure 19.16 shows a drilled shaft without a bell. Here, L1 = 6 m, L2 = 7 m, Ds = 1.5 m, cu(1) = 50 kN/m2, and cu(2) = 75 kN/m2. Find these values: a. The net ultimate point bearing capacity. Use Eqs. (19.23) and (19.24) b. The ultimate skin resistance. Use Eqs. (19.26) and (19.28) c. The working load, Qw (FS = 3) FIG. 19.16arrow_forward3. The following table shows the shear test results along the foliation surfaces of gneisses. The area of the discontinuity surface is 6.4*10-3 m2. a) Fill in the table b) Calculate the slip resistance parameters of the gnaysa ). (use millimeter paper) Experiment No. Shearing Normal Load Shearing Normal burden Tensile Stress (kg) (kg) (kg/cm2) (kg /cm? 1 750 500 1400 1200 3 1600 1400 4 2000 1800 2500 3500 6. 3000 4250arrow_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_forward
- a. 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_forwardPlease correct solutionarrow_forward
- Please solve fully. Thank youarrow_forward9. The following are the details for the backfill material in a vibroflotation project. D10=0.36 mm D20 0.52 mm D25=0.60 mm D50=1.42 mm D75 1.65 mm a. Find the suitability number. b. Determine the rating. c. Determine the sorting coefficient.arrow_forwardAt failure, the major and minor principal stresses on a triaxial test are 200 kPa and 110 kPa respectively. If the porewater pressure at failure is 25 kPa... Q: What is the sine of the angle of shearing resistance of the soil? Round off your answer to two decimal places.arrow_forward
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