【摘 要】
:
A laboratory experimental program performed on Wuhan sandstones was presented under monotonic loading, partial cyclic loading during loading path and sine wave
【机 构】
:
State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing 100084, China;Com
【基金项目】
:
Opening Research Foundation of the Chinese Academy of Sciences Key Laboratory of Rock and Soil Mechanics;China Postdoctoral Science Foudation;国家自然科学基金
论文部分内容阅读
A laboratory experimental program performed on Wuhan sandstones was presented under monotonic loading, partial cyclic loading during loading path and sine wave cyclic loading with different strain rates to compare uniaxial compression strength and elastic properties (elastic modulus and Poisson ratio) under different conditions and influence of pore fluid on them. When the loading strain rates are 10-5, 10-4 and 10-3/s, uniaxial compression strengths of dry sandstones are 82.3, 126.6 and 141.6 MPa,respectively, and that of water saturated sandstones are 70.5, 108.3 and 124.1 MPa, respectively. The above results show that the uniaxial compression strength increases with the increase of strain rate, however, variation of softening coefficient is insignificant.Under monotonic loading condition, tangent modulus increases with an increment of stress (strain) to a maximum value at a certain stress level, beyond which it starts to decline. Under the partial cyclic loading during loading path condition, unloading or reloading modulus is larger than loading modulus, and unloading and reloading moduli are almost constants with respect to stress level,especially unloading modulus. Under the sine wave cyclic loading condition, tangent modulus and Poisson ratio display asymmetric ’X’ shape with various strain, and the average unloading modulus is larger than the average loading modulus.
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