Strength characteristics and elastic modulus evolution of frozen gray sandstone under cyclic loading

The triaxial compression test and cyclic loading test were carried out on frozen sandstone samples cut from weakly cemented water-rich Mesozoic gray sandstones using TDW-200 frozen soil triaxial test apparatus. The strength characteristics and the evolution rules of elastic modulus were studied based on the experimental results. The test re- sults show that while the peak strength increases under low confining pressure,it decreases under high confining pres- sure in cyclic loading test;during the whole process of cyclic loading,the tendency of elastic modulus is consistent with the path of cyclic loading;for each hysteretic loop,the tangent modulus increases first then decreases with the increase of deviatoric stress,it has the same tendency with the increase of cycle number when the deviatoric stress is the same.