Centrifuge tests on behaviors of soft clay subgrade under cyclic loading

A couple of key test technologies for dynamic centrifuge modeling and the permanent deformation responses of saturated clay to cyclic loading are introduced. The rigid pavement is used in the model system. The subgrade base is simulated by using the compacted sand cushion. The modeling subsoil is Shanghai saturated soft clay in an over-consolidation state. The testing process and key test techniques are discussed, such as the reconstruction of saturated clay and the pre-loading consolidation with an given over-consolidation ratio in clay subsoil. The image analysis techniques (PIV) is also adopted for the calibration of deformation. Finally, a series of test results are given to reveal the cumulative deformation behaviors of saturated soft clay under cyclic loading. It is shown that the cumulative pore pressure increases rapidly and then decreases slowly. PIV indicates that the effective impact zone in the deformation of subsoil subgrade expands with the increasing number of load cycling.