Energy and Damage Evolution Characteristics of Rock Materials under Different Water Contents

To study the effect of water content on mechanical properties and energy damage of hard rock materials, the uniaxial compression tests were carried out on sandstone samples under different water contents. The test results show that with the increase of water content, the peak stress, brittleness index and elastic modulus of sandstone samples decrease, and the peak strain of sandstone increases. In the dry state, there is no obvious plastic deformation before failure, showing a significant brittle failure, while in the saturated state, there is a significant plastic deformation in the pre-peak stage, and a yield plateau before failure. The larger the water content of sandstone samples is, the stronger the energy absorption capacity is, the smaller the energy absorption rate is, but the more significant the energy dissipation phenomenon is. The smaller the water content of sandstone samples is, the larger the damage variable is at the time of failure, and the sandstone samples have a strong impact tendency at the time of failure in the dry state. The conclusions provide a theoretical reference for the stability control of surrounding rock in deep underground engineering.