ABSTRACT
A series of model tests of the slope called tilting box tests are carried out on different kinds of granular materials in dry and wet states. It is found that the surface slip, not the circular slip, occurs in the dry granular soil slope without cohesive forces (cohesion c=0), whereas the rigid body-slip with some depth simitar to the circular slip occurs in the wet granular soil slope with cohesive forces (cohesion c>0). The failure mechanism of the surface slip in the dry granular soil slope is successfully simulated by DEM (Distinct Element Method). Based on this failure mechanism, an effective reinforcement method to stop the motion of particles near the surface of the slope is proposed. Furthermore, a simplified direct box shear test is used to determine strength parameters under low confining stresses (less than 1kPa) near the slope surface, and the measured angles of internal friction of samples in dry state agree well with the slope angles at failure obtained by the tilting box tests.
