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基于弱黏结中砂岩经历400~1 000℃高温后进行物理力学参数测试,分析了高温后弱黏结中砂岩的物理力学参数与温度、围压的关系。结果表明:经历400℃以内高温对试样体积、质量和波速影响很小,超过400℃以后试样体膨胀率、烧失率随温度升高单调增加,波速随温度升高单调降低,经历400和800℃高温后试样的变形参数明显高于自然状态(25℃)单轴试验值,高温后试样的弹性模量和变形模量大幅度降低,极限应变随温度升高单调增加。试样的弹性模量、变形模量和峰值强度与围压呈正相关,试样峰值强度与围压符合Coulomb强度准则。经历800℃以内高温对试样黏聚力的影响不大,超过800℃以后黏聚力急剧降低。高温后试样的内摩擦角与温度呈正相关;经历1 000℃以内高温对弱黏结中砂岩具有强化作用,但超过800℃对试样材料强度有所弱化。Mohr-Coulomb预测理论破坏角与试验破坏角大致相当,试样的试验破坏角与围压呈负相关。
Based on the physical and mechanical parameters of weakly bonded sandstone after 400 ~ 1000 ℃ high temperature, the relationship between the physical and mechanical parameters and the temperature and confining pressure of sandstone in weakly bonded after high temperature was analyzed. The results show that the sample volume, mass and wave velocity have little effect when the temperature is up to 400 ℃. After over 400 ℃, the bulk expansion rate and burning loss rate increase monotonically with the increase of temperature. The wave velocity decreases monotonously with the increase of temperature. And 800 ℃, the deformation parameters of the sample are obviously higher than those of the natural state (25 ℃). After high temperature, the elastic modulus and deformation modulus of the sample decrease greatly, and the ultimate strain increases monotonically with increasing temperature. The elastic modulus, deformation modulus and peak strength of the specimen are positively correlated with the confining pressure. The peak strength and the confining pressure of the specimen conform to the Coulomb strength criterion. Experience 800 ℃ within the high temperature on the cohesion of the sample has little effect, more than 800 ℃ cohesion sharply reduced. After the high temperature, the internal friction angle of the sample is positively correlated with the temperature. Experiencing the high temperature within 1 000 ℃ can strengthen the weakly bonded sandstone, but the strength of the sample is weakened when it exceeds 800 ℃. Mohr-Coulomb prediction theory damage angle is roughly the same as the failure angle of the test, and the test failure angle of the Mohr-Coulomb model is negatively correlated with the confining pressure.