LAUSR

It is known that time-dependent rheological deformation of rocks is influenced by cyclic disturbance loads. However, the stress relaxation behavior after cyclic disturbance is still poorly understood. To study such effects, a dynamic disturbance electrohydraulic servo triaxial test system was developed. A series of disturbance relaxation tests with different disturbance numbers and amplitudes were carried out on marble at several strain levels. The influence of cyclic disturbance parameters on the relaxation magnitude, relaxation rate, and peak stress was analyzed. Relaxation magnitude and relaxation rate after cyclic disturbance loads are larger than those of conventional relaxation. In addition, sensitivity analysis reveals that the relaxation magnitude is more sensitive to the disturbance amplitude. Damage variables defined by the plastic strain method can well reflect the evolution law of relaxation damage under different disturbance conditions. It is believed that the damage model constructed by Harris function can better describe the relaxation damage evolution law at various strain levels.