Experimental and modeling study on shear creep behavior of joint rock

Unfilled joint rock in the surrounding rock mass of a huge underground cave in Longtan Hydropower Project was carried out shear creep experiment. Compared with the short-term shear strength parameters gotten by rapid shear experiment, the long-term shear strength parameters have some reduction. Moreover, the sensitivity of cohesion on the time is higher than that of internal friction angle. Based on shear creep curves of joint rock, five-component visco-elastic shear creep model is put forward to identify the curves that show the visco-elastic creep behaviors. Then by connecting Non-linear Visco-plastic Body (NVPB) and five-component visco-elastic shear creep model in series, we construct a new seven-component non-linear visco-elasto-plastic shear creep model of rock. Then using complete accelerative shear creep curve of joint rock, proposed seven-component non-linear shear creep model of rock is carried out the identification. The comparison between the shear creep model and experimental result shows that proposed non-linear shear creep model is right and reasonable.