3. A soil layer consists of 4 meters of sand underlying 5 meters of clay. The water table is nat- urally located at the rock bed under the soil strata but rose by 6 meters due to a recent storm. Further, capillary action is expected to develop due to the nature of the soil in ques- tion. Compute the effective stresses at the end of expected capillary action, at the end of the water table, at the interface of the clay and sand and finally at the bottom of the soil strata. Pertinent soil properties are as follows: Average S, Capil- lary Zone G, e D10 Clay 2.71 0.98 0.0125 25 55% Sand 2.74 0.93 N.A. N.A. N.A.

3. A soil layer consists of 4 meters of sand underlying 5 meters of clay. The water table is nat- urally located at the rock bed under the soil strata but rose by 6 meters due to a recent storm. Further, capillary action is expected to develop due to the nature of the soil in ques- tion. Compute the effective stresses at the end of expected capillary action, at the end of the water table, at the interface of the clay and sand and finally at the bottom of the soil strata. Pertinent soil properties are as follows: Average S, Capil- lary Zone G, e D10 Clay 2.71 0.98 0.0125 25 55% Sand 2.74 0.93 N.A. N.A. N.A.

Fundamentals of Geotechnical Engineering (MindTap Course List)

5th Edition

ISBN:9781305635180

Author:Braja M. Das, Nagaratnam Sivakugan

Publisher:Braja M. Das, Nagaratnam Sivakugan

Chapter8: Stresses In A Soil Mass

Section: Chapter Questions

Problem 8.10P: The soil profile at a site consists of 10 m of gravelly sand underlain by a soft clay layer. The...

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The soil profile at a site consists of 10 m of gravelly sand underlain by a soft clay layer. The water table lies 1 m below the ground level. The moist and saturated unit weights of the gravelly sand are 17.0 kN/m3 and 20.0 kN/m3, respectively. Due to some ongoing construction work, it is proposed to lower the water table to 3 m below the ground level. What will be the change in the effective stress on top of the soft clay layer?
A soil layer consists of 4 meters of sand underlying 5 meters of clay. The water table is naturally located at the rock bed under the soil strata but rose by 6 meters due to a recentstorm. Further, capillary action is expected to develop due to the nature of the soil in question. Compute the effective stresses at the end of expected capillary action, at the end ofthe water table, at the interface of the clay and sand and finally at the bottom of the soilstrata. Pertinent soil properties are as follows:
4.5 meters of clay underlain by 4.5 meters of sand. Water table is 3 meters from the ground level. Capillary action is expected to occur. Calculate the effective stresses at the end of the capillary zone, at the end of the water table, at the clay-sand interface and at the bottom of the soil layer. Pertinent soil properties follow: Clay: e = 1.01. Gs = 2.721, Average saturation at the capillary zone = 50%, C = 30 mm2 and D10 = 1/75 mmSand: water content of 32.4723%Void ratio: Assume logical 4 significant figure value.
A soil layer consists of 4 meters of sand underlying 5 meters of clay. The water table is naturally located at the rock bed under the soil strata but rose by 6 meters due to a recent storm. Further, capillary action is expected to develop due to the nature of the soil in question. Compute the effective stresses at the end of expected capillary action, at the end of the water table, at the interface of the clay and sand and finally at the bottom of the soil strata. Pertinent soil properties are as follows:
A soil profile, under surcharge load of 25 kN/m2 at ground level, consists of 6m sand and 3m clay layer. Ground water table is 2m below sand layer. Dry unit weight and saturated unit weight of sand is 15.80kN/m3 and 16.90kN/m3 respectively. Clay layer, Gs=2.67 and saturated unit weight is 18.80 kN/m3. Determine a)Increase in stress at the mid layer of clay b) With dewatering 2m, what is the stress increase at the mid layer of clay c) How much must the water level be lowered to me more effective than the surcharged load?
A layer of sand, 4m thick, overlies a layer of low permeability clay, 5mthick. The bulk unit weight of the sand is 16.5 kN/m3 and its saturatedunit weight is 18 kN/m3 . The saturated unit weight of the clay is 21kN/m3 . The water table exists initially at 1.0m below ground level butpumping will permanently and rapidly lower the water table to 3.0mbelow ground level.Determine the variation of total stress and porewater pressure at depthh in the clay and the long-term variation in effective stress.Calculate the initial (before pumping) and the long-term (afterpumping) effective stress at the middle of the clay layer.
The profile at a site consists of 5 m of sand overlying 10 m of compressible clay, which in turn overlies a dense sand. The water table is at the top of the profile. The total unit weight of the top sand is 19 kN/m3, and that of the clay is 18 kN/m3. The cv of the clay is estimated to be 5 x 10-3 cm2/sec. Initially the clay is normally consolidated. It is planned to place a temporary fill that will exert a vertical load of 200 kPa over the entire site. How long must the fill be in place so that, after it is removed, the maximum past pressure at every point in the clay is at least 50 kPa larger than the vertical effective stress that existed before the fill was placed?
A uniform loading of 150kPa is applied at a 28 m Χ 28 m area. Please calculate the consolidation settlement of the clay layer used the middle of the clay layer to estimate the stress increment with the influence factor method). Cc = 0.4, Cs = 0.04, preconsolidation stress is 150 kPa and unit weight of water is 10 kN/m3. What is the settlement at the corner and center of the loading? What is the differential settlement between the corner and the center?
A 2-meter clay layer (e = 0.88, Gs = 2.67, Cc = 0.305) is overlain with 4-meter-thick sand layer (e = 0.82, G = 2.72). The water table is at the interface of the sand and clay layer. If a 2-meter-thick land fill (γ = 17.97 kN/m3) is placed over the existing ground surface, compute the consolidation settlement (in mm.) of the clay layer. Hint: Use the land fill's resulting pressure on the ground surface as the stress increase. Round off to two decimal places. Selected Answer: 60.25
A sediment settling lagoon has a depth of water of 4 m above the clay base. The clay layer is 3 m thick and this overlies 4 m of medium sand, which in turn overlies impermeable rock. Given the unit weight of clay, medium sand and sediment of silty fine sand is 18 kN/m², 20 kN/m³ and 16 kN/m², respectively. Calculate the effective stress at the top of the clay and at the top and bottom of the second layer under the following condition; i) initial, before any sediment is deposited. ii) After a 2m layer of sediment of silty fine sand has been deposited. iii) After draining the lagoon down to base level, with the same thickness (2m) of sediment still in place
The soil profile consists of a 12 m layer of sand, 6 m layer of clay and incompressible bedrock.The water table is located 5 m below the ground surface. The weight of sand above the watertable is 17.9 kN/m3 below is 18.4 kN/m3 . The saturated weight of the clay is 18.2 kN/m3. Clayhas a compression index of 0.18 and a void ratio of 0.80. If the structure to be built on theground will increase the soil pressure by 100 kPa, determine the settlement of the clay layer.
A dense silt layer has the following properties: e =0.406 D10= 10.1 um Capillary constant = 0.209 sq.cm Free ground water level is 8m below the ground surface. 1.) Find the height of capillary rise in the siltin meters. 2) Find the vertical effective stress at 6m depth. Assume ys = 26.51 kn/m3 and the soil above capillary action rise and ground surface is partially saturated at 79%.