7.11 A 2 m wide continuous foundation is to be placed in a saturated clay at 1.5 m depth where cu = 40 kN/m² and y= 18.0 kN/m³. a. What is the ultimate bearing capacity of the foundation? b. To increase the ultimate bearing capacity, it is proposed to place dense sand ('= 42° and y = 18.5 kN/m³) in a trench directly beneath the foundation to a depth of 4.0 m. The width of the trench is the same as the width of the foundation. What is the new ultimate bearing capacity of the foundation?