ASSIGNMENT
Problem 1. A 2m x 3m foundation shown below is subjected to the loads indicated. Determine the factor of safety using Merrhors effective area method.
Problem 2; A 2.0 m wide continuous foundation is placed at 1.5 m depth in a saturated clay where c, = 40 kbUm’ and y = 17 kN/m’. At 2.0 m below the ground level, this clay layer is underlain by a stiffer clay where s = 60 kN/m• and y = 18 kN/m’. What would be the maximum wall load allowed with ES — 4? Use Eq. 7.11.
Problem 3; A 2 m wide continuous foundation is placed at I m depth within a 1.5 m thick sand layer (4)’ = 30°, y = 18 kN/m’) that is underlain by a weaker clay layer (undrained shear strength = 27 MVOs’ y = 19.5 kNinf). What would be the maximum wall load allowed with es = 4?
Problem 4; A square foundation of B =4 m applies a uniform pressure of 17.5 kblins’ to the underlaying ground. Determine the vertical stress increase using at a depth of lin below the center using: a) 2:1 method b) m and n method (Table 8.5) c) Stress isobars (Figure 8.10) d) Newmark Method (See powcrpoint for chart)
problem 5; B 6fi CUE 211 E D 0 411 A 411 Using the m and n method and Table 8.5 find the change in stress I Oft below point 0 below with a load of 2I6kips applied
Problem 6. Design a square foundation to be embedded 3ft in the sand layer at a site with a soil profile as shown in Figure below, to support load of 50 kips. The design criteria are FS=3and maximum tolerable settlement is 1 in.
2m(610
Sand 3 m (10 It) Tnaxial tests- o„. 37′, y = 16 5 ktilm3 (105 pd). 17 kNim3 (108 Pd). = 45 MPa (940 ks1). V=0.3
Stitt clay 2,6ftt Triax(al test 4„ = 60 kPa (1250psf). or = E„ = 40 MPa (835 ks15. v’= 0.35. Consoldation tests: OCR = 5. C, = 0.3, C, = 0.05 Phys.’ tests = = 35ao, G, = 2.7
13 m (40 ft) Dense gravel N. 52 (average)
