Study on mechanical properties and statistical damage constitutive model of red sandstone after heating and water-cooling cycles

Abstract

The repeated action of high temperature and water cooling will have a strong deteriorating effect on the mechanical properties of the rock, which will eventually lead to the damage and cracking of the rock. In order to study the influence of heating and water-cooling cycles on rocks, the P-wave velocity and mechanical properties of red sandstone after heating and water-cooling cycles were tested. Meanwhile, based on the Weibull distribution theory, a statistical damage constitutive model based on Mohr-Coulomb strength criterion considering the effects of heating and water-cooling cycles was established, and verified based on the results of triaxial tests. The results show that the P-wave velocity and peak intensity decrease with the temperature under the same number of cycles. The elastic modulus will decrease with the temperature and the number of cycles, indicating that the red sandstone will gradually soften and the ductility will increase under repeated high temperature and water-cooling cycles. And the model can well reflect the stress-strain curves of different high temperature and water-cooling cycles. The research results can provide analytical theories and methods for geothermal development projects.