Experimental and theoretical studies on the effects of water content on shear creep behavior of weak structural plane of sandstone

Creep behavior of weak structural plane is one of the most important mechanical characteristics of rock mass and always has an important influence on deformation and long-term strength of rock mass.Water content of the fillings is a significant factor influencing the creep properties of the weak structural plane.In this study,by multi-stage loading,a series of shear creep tests on the weak structural plane of sandstone with different water contents are conducted.The curves of the shear creep deformation vs.time under different water content of the fillings are derived.The effects of water content on the shear creep behavior and long-term shear strength of weak structural plane of sandstone are analyzed.Compared with the shear strength by rapid shear test,the long-term strength has sharply decreased.Based on the test results and analysis,modified viscoelastoplastic model is identified to describe the behavior of water content influencing on the weak structural plane of sandstones and parameters of this model are also given through back analysis.