ABSTRACT
Many of the traditional methods of geotechnical engineering design are based on the concepts of plasticity rather than elasticity. Typically, conditions at collapse are investigated, and a factor is applied to one of the parameters involved in the calculation to arrive at the final design. This factor, usually given the symbol F, is conventionally known as the factor of safety. This is something of a misnomer, because its purpose is not only to ensure that collapse will not occur under working conditions, but also that deformations will be small.
