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为研究饱水度和围压对砂岩力学特性的影响,在不同围压和饱水度下开展三轴试验,获得了不同饱水度和围压下巴里坤砂岩的模量、峰值强度和残余强度,分析了饱水度和围压对砂岩模量、峰值强度和残余强度的影响规律,结果表明:(1)围压增加,砂岩的模量也增加,围压与模量之间近似为直线关系;饱水度增加,砂岩模量降低,单轴下饱和砂岩的模量降低50.9%;饱水度与砂岩模量之间近似服从直线或负指数函数关系。(2)饱水度增加,峰值强度下降;单轴条件下饱和砂岩的峰值强度下降了44.2%;饱水度与砂岩峰值强度之间近似服从自然对数关系。(3)强度退化指数可以较好地描述围压对残余强度的影响,巴里坤砂岩的强度退化指数与围压之间近似符合负指数关系;随着饱水度增加,砂岩的残余强度降低。(4)随着围压增加,饱水度对砂岩模量、峰值强度和残余强度的影响都减弱。(5)饱水度在60%以下时,饱水度变化对模量和峰值强度的影响显著,当饱水度超过60%后,模量和峰值强度仍随着饱水度增加而降低,但变化速率趋缓;对于残余强度,则饱水度在80%以下时影响显著。
In order to study the effect of saturation and confining pressure on the mechanical properties of sandstone, triaxial tests were carried out under different confining pressures and water saturations to obtain the modulus, peak intensity and residual of Balikun sandstone under different water saturation and confining pressure The results show that: (1) As the confining pressure increases, the modulus of sandstone also increases, and the relationship between confining pressure and modulus is approximately The relationship between the saturated water content and the sandstone modulus is linearly or negatively exponential. (2) The water saturation increases and the peak intensity decreases; the peak intensity of saturated sandstone decreases by 44.2% under uniaxial conditions; and the natural logarithm of the relationship between water saturation and sandstone peak intensity approximates to that of natural sandstone. (3) The strength degradation index can describe the effect of confining pressure on the residual strength. The relationship between strength degradation index and confining pressure of Balikun sandstone is approximately negative exponential relationship. With the increase of saturation, the residual strength of sandstone decreases. (4) With the increase of confining pressure, the effect of saturated water on the sandstone modulus, peak intensity and residual strength are weakened. (5) When the saturated water content is below 60%, the influence of saturated water content on modulus and peak intensity is significant. When the saturated water content exceeds 60%, the modulus and peak intensity decrease with the increase of water saturation. But the rate of change slows down; for residual strength, the effect is significant when the saturation is below 80%.