EXPERIMENTAL STUDY ON INFLUENCING FACTORS OF DYNAMIC SHEAR MODULE AND DAMPING RATIO OF FAULT GOUGE

Dynamic shear modulus and damping ratio test of fault gouge with different dry density values or water contents are performed using GDS resonant column system. The results show that the relationship between dynamic shear modulus and dynamic shear strain can be well fitted by Hardin-Drnevich hyperbolic model. The dynamic shear modulus and the damping ratio both increase with the dry density, while decrease with water content. Experimental points of normalized dynamic shear modulus are mainly located in the range of the G/G_max~γ curve of sand which is proposed by Seed and Idriss, and in accordance with the trend of cohesive soil which is proposed by Sun and Seed. The damping ratio changes linearly with the dynamic shear strain under semilog coordination. The fitting formula is suggested.