Ultimate bearing capacity (qu): It is the gross pressure at the base of the foundation at which the soil fails in shear is called as ultimate bearing capacity.
Safe bearing capacity (qs) : It is the maximum pressure which the soil can carry without risk of failure is called as safe bearing capacity
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Ultimate Bearing Capacity (qu):- The Ultimate bearing capacity of soil is defined as the minimum gross pressure intensity at the base of the foundation at which the soil fails in shear.
Safe Bearing Capacity (qs):- The maximum pressure the soil can carry safely without risk of shear failure is called the safe bearing capacity. It is equal to the net safe bearing capacity plus the original overburden pressure. Sometimes the safe bearing capacity is also referred to as the ultimate bearing capacity qu divided by factor of safety F.