Study On Mechanical Properties Of Rock Under Temperature And Confining Pressure

In order to ensure the safety of cold regions engineering, which is conducting in a largeof number, the further study of mechanical properties of frozen rock is becoming more andmore important. Based on the damage mechanical theory of rock, this paper studied thedamage mechanical properties of rock under load and Freeze-thaw cycles coupling in coldregions, and analyzed the process of rock sample compression test in the low temperatureenvironment by simulation.Based on the basic theory of damage mechanics, using the generalized strain equivalenceprinciple, the damage variable of rock under load and freeze-thaw cycles coupling was pulledin, and the damage evolution equation of rock under load and freeze-thaw cycles couplingwas established in the situation considering the freeze-thaw cycles and confining pressure,then the damage constitutive relation of rock under load and freeze-thaw coupling wasdetermined by deducing the expression of the model parameters. The damage constitutivemodel of rock under load and freeze-thaw cycles was inspected and verified by using theexperimental data of triaxial compression test of rock in room temperature and the uniaxialcompression test of rock after freeze-thaw cycles, and the model parameters in the wereanalyzed, proving the rationality of the model.Using the finite element calculation software, the numerical simulation of rock sampleunder different confining pressures and temperatures were carried out for analyzing theinfluence of confining pressure and temperature on the mechanical properties of rock. Thetransient thermal-mechanical coupling analysis were applied in uniaxial force state of rocksample under the low temperature environment without frost heave and including frost heaverespectively to study the influence of frost heave on the mechanical properties of lowtemperature rock and the force characteristics under thermal-mechanical coupling. The resultsshowed that the confining pressure and low temperature cloud improve the carrying capacityand frost heave had a significant effect on the stress distribution on the low temperature rock.