高温作用对煤系砂岩力学性能和能量演化机制的影响

Influence of high temperature treatment on mechanical properties and energy evolution mechanism of sandstone

为了研究高温作用对煤系砂岩力学性能和能量演化机制的影响,采用自行研制的高温加热系统和RMT-150B岩石力学测试系统对煤系砂岩进行加热和单轴压缩试验,探讨砂岩强度、变形特征和能量特征随温度的变化情况。结果表明:高温作用后煤系砂岩单轴压缩应力-应变曲线随温度升高表现趋势大致相同,且煤系砂岩逐渐由脆性向塑性转变;不同温度作用后的煤系砂岩峰值强度和弹性模量随温度升高表现出不同程度降低,峰值应变随温度升高大幅增加;经历不同温度作用后的煤系砂岩总应变能和弹性能与温度呈正相关关系,耗散能与温度呈负相关关系;温度对煤系砂岩的破坏模式有显著影响,温度升高使煤系砂岩的破坏形态由单斜面剪切破坏向多剪切面破坏发展。

In order to study the influence of high temperatures treatment on mechanical properties and energy evolution mechanism of coal measures,the self-developed heating system and RMT-150B mechanical testing system were used to conduct heating and uniaxial compression tests on coalmeasures sandstone. The regularities on the strength and deformation characteristic with temperature varying were discussed. The experimental results showed that the uniaxial compression stress-strain curve of sandstone showed the same trend with the increase of temperature and the sample changed from brittleness to plasticity with temperature rising. The peak strength and elastic modulus of sandstone decreased with the increase of temperature,while the peak strain increased obviously with the increase of temperature. The total strain energy and elastic energy of sandstone were positively correlated with temperature,while the dissipated energy was negatively correlated with temperature. Temperature had a significant influence on the failure mode of sandstone,the failure pattern of sandstone developed from single-slope shear failure to multi-shear failure as temperature rising.