Consider a circularly loaded flexible area acting on the ground surface. The radius of the circular area is 20 ft and the uniformly distributed load is q = 1,000 lb/ft2. Calculate the vertical stress increase, Δσz, at a depth of 10 ft for a radius of 0 ft (immediately below the center of the circular area) and 20 ft (immediately below the edge of the circular area).

Consider a circularly loaded flexible area acting on the ground surface. The radius of the circular area is 20 ft and the uniformly distributed load is q = 1,000 lb/ft². Calculate the vertical stress increase, Δσ_z, at a depth of 10 ft for a radius of 0 ft (immediately below the center of the circular area) and 20 ft (immediately below the edge of the circular area).