(1. Beijing Key Laboratory of Urban Oil and Gas Distribution Technology，China University of Petroleum，Beijing 102249， China；2. Beijing Geotechnical Institute Engineering Consultants Co.，Ltd.，Beijing 100038，China；3. China Petroleum West-East Gas Pipeline Company，Shanghai 200122，China)
Abstract：The granite samples were drilled form a proposed underground gas storage site in Jinzhou，Liaoning Province. The mechanical tests(uniaxial and triaxial) were conducted under different freezing temperatures(－10 ℃– －50 ℃) and different moisture conditions(fully saturated and dry). Then the law of rock deformation，compressive strength of samples，and the relation between the shear strength parameters and the freezing temperatures were analyzed. The test results show as follows：(1) Whether the granite samples are dry or fully saturated，the uniaxial and triaxial compressive strength increased nonlinearly with the decrease of temperature. There is a threshold temperature below which the strength of granite becomes to stabilize. The effect of the low temperature on the mechanical properties is more obvious for saturated samples. (2) The cohesion increased significantly with the decrease of low temperature. For dry samples，the internal friction angle remained at about 57°. The internal friction angle of fully saturated samples increased about 3.43% when the temperature dropped from －10 ℃ to －50 ℃. In the freezing conditions，the moisture condition has an important impact on the change of the shear strength parameters. The results provide helpful insights for the construction of liquefied natural gas (LNG) storage at low temperature.
