Study on a Damage Model and Uniaxial Compression Simulation Method of Frozen-Thawed Rock

To evaluate the deterioration degree of rock freeze-thaw damage in cold area engineering, it is necessary to establish an accurate freeze-thaw rock damage model and its uniaxial compression numerical simulation method. Therefore, indoor freeze-thaw cycle tests of saturated yellow sandstone were carried out. The porosity and P-wave velocity were measured, and uniaxial compression tests were conducted after different numbers of freeze-thaw cycles. The findings indicate that with an increasing number of freeze-thaw cycles, the elastic modulus, peak strength and wave velocity of the yellow sandstones gradually decrease, while the peak strain and the average porosity increase. The energy evolution law with different numbers of freeze-thaw cycles was analyzed, a freeze-thaw damage model was established according to the relative change in the dissipated energy ratio before and after freezing-thawing, and the accuracy of this damage model and five common damage models was evaluated by the uniaxial compressive strength and peak strain. The functional relationship between mesoscopic parameters and the number of freeze-thaw cycles was formulated to establish a numerical simulation method for saturated sandstones under uniaxial compression after freeze-thaw cycling. The reliability of the numerical method was verified by comparing the stress-strain curve, peak stress, peak strain and energy law with the experimental results.