soil can withstand without undergoing shear failure.
qn = qf - qo
Here, qo represents the overburden pressure at foundation level and is
equal to үD for level ground without surcharge where ү is the unit
weight of soil and D is the depth to foundation bottom from Ground
Safe Bearing Capacity (qs) : It is the safe extra load the foundation
soil is subjected to in addition to initial overburden pressure.
Here. F represents the factor of safety.
Allowable Bearing Pressure (qa) : It is the maximum pressure the
foundation soil is subjected to considering both shear failure and
Foundation is that part of the structure which is in direct contact with
soil. Foundation transfers the forces and moments from the super
structure to the soil below such that the stresses in soil are within
permissible limits and it provides stability against sliding and
overturning to the super structure. It is a transition between the super
structure and foundation soil. The job of a geotechnical engineer is to
ensure that both foundation and soil below are safe against failure and
do not experience excessive settlement. Footing and foundation are
Modes of shear failure
Depending on the stiffness of foundation soil and depth of foundation,
the following are the modes of shear failure experienced by the