Triaxial compression test of frozen saturated sandstone under real-time action of pore water
To study the mechanical properties of frozen saturated sandstone under real-time action of pore water pressure,the triaxial mechanical properties of sandstone are analyzed under four different in-situ stress levels at both room temperature(20 ℃)and sub-zero temperatures(-5 ℃),considering var-iations with and without pore water pressure.And the microscopic scanning electron microscope test was carried out on the sandstone samples before and after freezing.The results show that low temperature freezing can enhance the triaxial compressive strength of sandstone samples,and the pore ice formed af-ter freezing can restrict the flow of pore water.The pore water pressure weakens the triaxial compressive strength of sandstone at room temperature and sub-zero temperature,with a more pronounced effect ob-served at room temperature.With the increase of in-situ stress,the weakening effect of pore water pres-sure on the triaxial compressive strength of sandstone samples becomes stronger at room temperature,and vice versa at negative temperature.The elastic modulus of sandstone frozen with pore water pressure is generally lower than that of sandstone frozen without pore water pressure under the same ground stress condition,and the elastic modulus increases first and then gradually and decreases with the increase of ground stress.The loading failure surface of sandstone samples at room temperature is mostly smooth shear failure,and the failure surface is mostly'S'after freezing.There are more frozen scattered parti-cles and debris in the microstructure of sandstone samples with pore water pressure,especially under freezing condition.
frozen sandstonepore water pressuretriaxial compressionstrength evolution rulemicro-structure
万方数据
维普
