Drained Permanent Deformation of Sand Due to Cyclic Loading

Due to cyclic loading, a soil sample may be either densified or loosened accompanied with cumulative shear deformations. The cumulative volume change and shear deformation behavior depend significantly on the static stress state existing prior to the application of cyclic loading. Based on the principle of energy balance, during cyclic loading, the work done on a soil sample is dissipated in rearranging particles, thus creating irrecoverable strains. Using the concept of critical‐state soil mechanics, a relationship is obtained between the dissipated energy and the cumulative strains. Based on this relationship, a simple expression is derived to relate the static stress state and the ratio of cumulative volume to cumulative shear strains (i.e., the first to the second strain invariants). The derived relationship is used to illustrate the dilative and contractive characteristics of sand under cyclic loading. This relationship is also validated by comparing the predicted results with the measured ones obtained from cyclic triaxial tests on sands.