Question 2. A 500-mm diameter, 15-m deep drilled shaft foundation is to be constructed in the soil profile shown below. The design axial load is 700 kN. The factor factor of safety for downward loading is 3.0, and the factor of safety for upward loading is 6.0. Compute the allowable downward and upward loads capacity and determine if the design is acceptable. 4.0 m Drilled shaft 15:0 m Medium Clay f₁ = 30 kPa Groundwater table Stiff Clay = 60 kPa = 2000 kPa

A standard penetration test has been conduted at a depth of 15 ft in an 8-inch diameter exploratory boring using a USA-style safety hammer and a standard sampler. This test produced an uncorrected N-value of 12. The soil inside the sampler was a fine-to-medium sand with Dsq = 0.6 mm. The vertical effective stress at this depth is 1100 lb/ft². Adjust the N- value as described in Class handout, then compute the relative density and classify the soil using Table 3.3.

Show solution with clear drawings

Determine the cohesion