Ring-shear Test and Constitutive Model of Surfaces between Clay in Nanchang Area and Different Roughness Contact

The shear failure characteristics of soil-structure planes are the internal mechanism of slip deformation of foundation structures and strata, and it is an inevitable and important problem in engineering. In this paper, the shear tests of silty clay and structural planes with different roughness in Nanchang area are carried out by using the modified shear apparatus, and the statistical piecewise constitutive model of shear damage based on Weibull distribution is established. The results show that the shear stress-shear displacement curves of contact surfaces with different roughness exhibit strain hardening and strain softening phenomena; the peak shear strength and the final residual strength of the contact surface increase with the enhancement of the roughness of the contact surface and the normal stress applied on the contact surface; the statistical piecewise constitutive model of shear damage based on Weibull distribution achieves the elastic-plastic properties of the contact surface well. The strain softening phenomena at the deformation stage after the peak value is in good agreement with the experimental curves.