Experimental study of fatigue deformation and damage characteristics of salt rock under cyclic loading

Testing study is made on the strength, deformation and fatigue damage process of salt rock under uniaxial compression condition by the rock mechanics test equipment RMT-150C. The results indicate that when the maximum of cyclic load is above "threshold value", the fatigue axial deformation can be divided into three stages: initial deformation, constant velocity deformation and accelerating deformation. Changing the maximum and average cyclic load, can affect the process of fatigue failure obviously; the initial axial deformation and cyclic axial deformation ratio will be increased; the total cyclic numbers reduced, while increasing the maximum of cyclic load and average cyclic load. Testing results show that the fatigue failure curve of salt rock is also controlled by complete stress-strain curve under static loading; the error is controlled under 10 percent. The deformation module of salt rock also can be divided into three stages: first, deformation modulus increasing; second, deformation modulus is in slightly decreasing trend; third, deformation modulus decreasing sharply. The damage development and deformation law of salt rock under cyclic loading are analyzed.