Study on Creep Characteristics of Saturated Sandstone under Graded Loading with Different Water Pressure

Rock mass in the water-level fluctuation zone of bank slope of the Three Gorges Reservoir area has been saturated for a long time during the process of water level rise and fall. In order to study the deformation characteristics of the internal rock mass, the rock mass on bank slope of the reservoir is selected, standard rock samples are made according to relevant regulations, and TOP INDUSTRIE multi-functional rock triaxial test system is used. Creep test of saturated sandstone has been carried out under three states: no water pressure, with water pressure and circulating water pressure. The results show that: (1) The creep deformation of saturated sandstone is the largest in the state of circulating water pressure, the next in the state of water pressure, and the smallest in the state of no water pressure. (2) There is a positive correlation between steady state creep rate and creep deformation of saturated sandstone. (3) The influence of circulating water pressure on the circumferential deformation of saturated sandstone is greater than that on the axial deformation. In the stage of failure stress grade, the effect of circulating water pressure on the circumferential deformation of saturated sandstone is obvious. (4) The cyclic water pressure greatly reduces the long-term strength of saturated sandstone, and the saturated sandstone under the cyclic water pressure is the first to be destroyed.