Strength and Dilatancy of Overconsolidated Clays in Drained True Triaxial Tests

摘要

The long-term mechanical behavior of overconsolidated (OC) clays in three-dimensional (3D) stress states plays an important role in many geotechnical problems, such as slope failures. However, previous experimental studies of OC clay were carried out under undrained conditions. This paper presents the results of a series of drained true triaxial tests on normally consolidated (NC) and OC clays. The stress paths were maintained in the same π-plane with Lode angles of θ = 0-60°. The test results show that OC clays exhibit positive dilatancy tendencies and greater shear strengths and smaller strains to failure than NC clays. The shear strength and dilatancy are largely influenced by the Lode angle. As the Lode angle increases, the shear strength and dilatancy decrease. The decreasing gradients of shear strength and dilatancy versus Lode angle are almost the same, indicating that the constitutive models for OC and NC clays can share the same rules for strength and dilatancy. The formation of shear bands in the θ = 60° specimens appears to have caused the abnormal test results in that case.