Dynamic Compaction Characteristics for the Unsaturated, Undrained Conditions of Soil under Cyclic Loading

Abstract

Multiple passages of agricultural equipment over soil impose a cyclic loading condition on soil. In response to such loading, the soil may yield by shear and compression. The resistance characteristics of soil to repetitive uniaxial loading is investigated for the consolidated undrained conditions of an unsaturated soil. In addition, the static undrained strength of the soil is determined from an unsaturated UU test. The cyclic stress ratio was employed in the evaluation of the relationship between axial load and the number of cycles Nc. It was not possible to ascertain the interrelationship between the effective stress, Nc and frequency for cyclic stress ratios higher than 0.4. As a result of the gain characteristics, there seemed to be a cyclic stress ratio at which the axial deformation was a maximum. Also, a rapid build up of pore water pressure was observed to lead to an early yielding of the soil.