Investigation on Damage Characteristic and Constitutive Model of Deep Sandstone under Coupled High Temperature and Impact Loads

To investigate the coupling damage characteristics of rock after high-temperature treatment under impact load, dynamic uniaxial compression tests for deep sandstone specimen laboratory conditions varying with high temperature (i.e., 25°C, 100°C, 300°C, 500°C, 700°C, and 900°C) strain rate 170 s-1, 205 240 s-1) were performed using splitting Hopkinson pressure bar (SHPB) system. Coupling variable was deduced based on Lemaitre equivalent theory. Moreover, parameters systematically determined according to test data, effects growth curves investigated. Finally, a compound constitutive model, which could consider damage, established verified describe mechanical characteristic sandstone. Theoretical experimental results indicated that simulated stress-strain matched data well proposed model reflect temperature-induced weakening strengthening effect.