The initial principal stresses at a certain depth in a clay soil are 100 kPa on the horizontal plane and 50 kPa on the vertical plane. Construction of a surface foundation induces additional stresses consisting of a vertical stress of 45 kPa, a lateral stress of 20 kPa, and a counterclockwise (with respect to the horizontal plane) shear stressof 40 kPa. Determine the change shearing stress in kPa.

Problem 1. A rectangular foundation 4m x 6m transmits a stress of 100 kPa on the surface of a soil deposit. Plot the distribution of increases of vertical stresses with depth under points A, B, and C up to a depth of 20m. At what depth is the increase in vertical stress below A less than 10% of the surface stress?

A planned construction site is underlain by a thick deposit of normally consolidated clay soil. A building foundation 6 ft square will be located on the ground surface and carry a total loading of 180,000 lb. Determine the foundation settlement (beneath center) by analyzing the volume changes due to primary compression in layers that are 2, 4, and 6 ft thick, respectively, from the foundation level downward. For simplification, assume a soil unit weight of 115 pcf constant with depth, an inplace void ratio of 1.05, and a compressio index of 0.35 for each layer analyzed. Use Boussinesq conditions.

A rectangular foundation (8x6 ft) carrying an axial load of 350 Kips is constructed on the soil profile shown below. Determine: a) The total stress, effective stress, and pore water pressure at the top, middle, and bottom of the clay layer (Normally Consolidated) after a very long time b) The final consolidation settlement of the clay layer caused by construction of the foundation (Use the weighted average method) c) The settlement of the clay layer after 2 years d) The degree of consolidation at the middle of clay layer after 4 years e) How long it takes for the clay layer to reach 95% degree of consolidation? 350 kips 5 ft 8 ft dry sand Ya-110 Pef 15 ft Yuu-115 Pef 30 ft Your-119 Pef 6 ft GWT sand NC Clay C-0.32;C-0.06 C.-4.5x10 cm²/sec Coarse sand

A circular foundation (D = 6 m) is built on a construction site where the soil profile is shown in Figure 5 below. The circular foundation applies a uniform pressure of 80 kPa to the surface of clay. The properties of the clay are: Specific gravity, G₁ Saturated unit weight at Compression index Ce Recompression index Cr Consolidation coefficient, c Over-consolidation ratio, OCR 10 m 6m Ø Clay Impervious rock Figure 5 2.6 20 kN/m³ 0.25 0.10 2.5 m²/year 1.2 (b) Calculate the stress increase at the center of the clay layer and 1) beneath the foundation center and 2) beneath the edge of the foundation; (c) Calculate the consolidation settlement beneath the center of the foundation due to the stress increase; (d) Determine the settlement at the center of the clay after 1 year of applying the pressure; (e) A 50 mm thick clay sample was taken from the site and consolidated in the oedometer, how long it will take for the clay to reach 90% consolidation?

Estimate the increase in vertical stress at 0.5 m depth intervals, within the clay layer, below point A (See figure below). The foundation exerts a uniform vertical stress of 120 kPa at ground level. Using these values estimate the settlement due to the clay layer. (Hand in any graphs used) 5m 5m 2m 3m Very Dense Sand 2m 1.5m Clay E=3.5 MPa 2m Bedrock Soil profile A Plan of building 3m Soil profile and plan for Question 4 3m FA

A 100'x50' mat foundation (also called slab-on-grade) will be placed at the site shown in Figure 1. Calculations show that the foundation will cause an average increase in vertical stress in the clay layer of (a) 850 psf under the foundation center, and (b) 350 psf under the foundation corner. Find the foundation settlement due to the consolidation of the clay layer both at the foundation center and the foundation corner. Can the resultant differential settlement be considered tolerable? Sand Clay Bedrock 2.5 ft 5 ft 5 ft 7-100pcf 122.5pcf, eo=1, op=1000psf Cc-0.5, Cs-C-0.1 Figure 1.

A 300 mm X 450 mm plate was used in carrying out a plate loading test in a sand, where the plate settled 5 mm under the applied pressure of 250 kN/m?. a. What is the coefficient of subgrade reaction for a 300 mm wide square plate? b. What would be the coefficient of subgrade reaction of a 2 m X 3 m foundation?

7.14 Refer to Figure 7.15. For a foundation on a layer of sand, given: B = 5 ft, L = 10 ft, d = 5 ft, B = 26.6°, e = 0.5 ft, and & = 10°. The Pressuremeter testing at the site pro- duced a mean Pressuremeter curve for which the pam) versus AR/R, points are as follow. AR/R. (1) P,(m) (lb/in.?) (2) 0.002 7.2 0.004 24.2 0.008 32.6 0.012 42.4 0.024 68.9 0.05 126.1 0.08 177.65 0.1 210.5 0.2 369.6 What should be the magnitude of Q, for a settlement (center) of 1 in.? Foundation BxL В Figure 7.15 Definition of parameters-B,