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

An SPT test was conducted in a dry sand (no ground water table) with a unit weight of 18kN/m3. The drill rig used had an energy efficiency rating of 60%. The recorded blow counts were 6, 7 and 8. The depth of testing was 6 m. Use the Liao and Whitman (1986) correction for overburden stress to determine the corrected SPT value at this depth. N60=? CN=? (use 3 decimals) N1(60)=? (truncated to an integer value)

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.

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