Mechanical Properties of Gas Storage Sandstone under Uniaxial Cyclic Loading and Unloading Condition

In order to study the mechanical properties and damage evolution of gas storage surrounding rock under periodic injection-production process, uniaxial cyclic loading unloading tests sandstone were carried out by TFD-2000 microcomputer servo-controlled triaxial testing machine. Results shown that compressive strength specimens gradually decreases with increasing stress amplitude after 200 cycles. The stress-strain curve condition formed hysteresis loops, loop presented sparse-dense-sparse when was relative higher. residual strains can be divided into three stages decay deformation stage, stable stage accelerated is 8~32 MPa, this phenomenon very similar creep behavior rocks. energy analyzed low which also discussed in detail, variable defined dissipative ratio accumulation well reflect development unloading. A nonlinear visco-plastic body proposed considering accelerate curves axial strains, used replace traditional Nishihara model, a viscoelastic-plastic model for loads established applicability verified. research results provide certain reference value construction maintenance storage.