Thixotropy can be described as a process of softening caused by remoulding, followed by a time dependent return to the original harder state at a constant water content and constant porosity. The shear strength increase of clays after remoulding can have a significant influence in practical engineering design. Thixotropy of clays with various index parameters are studied in this paper. Fall cone tests and direct simple shear (DSS) tests with bender element are performed to measure shear strength and Gmax with time after remoulding. DSS tests are also carried out to measure shear strength after reconsolidation following periods with thixotropic strength increase to check reconsolidation effect on thixotropy. The results show that both shear strength and shear modulus increase due to thixotropy, and their trends are similar. Thixotropic strength recovery is destroyed by reconsolidation to in situ effective stress. Thixotropy strength ratio increases with increasing sensitivity, plasticity index, liquidity index and water content.
Shaoli Yang, Yubin Ren, Knut H. Andersen, Ying Wang, Graziella M. F. Jannuzzi and Rhamira D. G. Pascual
Keywords: thixotropy, remoulded shear strength, shear modulus, plasticity, minerology, clay content
Publisher: DFI