A strip footing, 5 m wide, is founded on the surface of a deep deposit of clay. The undrained shear strength of the clay increases linearly from 3 kPa at the surface to 10 kPa at a depth of 5 m. Estimate the vertical ultimate load assuming that the load is applied at an eccentricity of 0.5 m right from the center of the footing's width. (Hint: Try a circular failure surface, determine the equation for the distribution of shear strength with depth, and integrate the shear strength over the radius to find the shear force.)