EXPERIMENTAL STUDY ON THERMO-MECHANICAL AND HYDRO-MECHANICAL COUPLING OF SANDSTONE FOR WEST ROUTE OF SOUTH-TO-NORTH WATER TRANSFER PROJECT

Based on the condition of the west route of South-to-North Water Transfer Project in China,the triaxial compression tests under confining pressures(from 0 to 60 MPa) coupled with temperatures(form 20 ℃ to 70 ℃) as well as confining pressures(from 25 to 60 MPa) coupled with pore water pressure(from 0 to 10 MPa)have been conducted on sandstone specimens.The results show that,at the same temperature,the strength of the rock increases with the confining pressure;but the deformation modulus doesn′t change distinctly with confining pressures.The influence of temperature on the strength and deformation properties is complex.The strength increases with the temperature when the confining pressure is lower than 40 MPa;whereas,when the confining pressure is greater than 40 MPa,the strength tends to decrease with the increasing temperature.It is also indicated that the deformation moduli generally increase with the increasing temperature.Under the condition of pore water pressure,it is shown that the strength of the rock increases with increasing of confining pressure and pore water pressure,and the deformation moduli of the rock increase with the increasing confining pressure and decrease with the increasing pore pressure.