Shear Strength of Sand under Pulsating Loading Condition

The dynamic shear strength of soil is one important problem in the earthquake engineering. In this field, there are many studies that Professor H.B.Seed carried out by the dynamic triaxial test and the dynamic simple shear test. Recently, the dynamic direct shear test of sand was carried out in our laboratory. This test apparatus consisted essentially of a shear box, an arrangement for applying a cyclic load to the soil and an electronic recording system. The entire assembly is shown in Fig. 1. A cyclic load was generated by a aircylinder and a cyclic period was controled by solid state timers. In these experiments, the shear strength of dry and wet sand under cyclic loading condition with 2 seconds cyclic period were obtained. From this results, we could find the difference between the static and the dynamic strength but we could still not clear this cause. We will continue these studies.