摘要
The time-dependent behaviors of coal and rocks were easily ignored. Besides, “three-stage” triaxial loading and unloading mechanics tests of sandstone were conducted based on the idea of the initial high in-situ stress state recovery according to the full-life cycle evolution characteristics of surrounding rocks in deep mines(pre-excavation,excavation and post-excavation). The time-dependent stress-strain curves of sandstone were obtained. Meanwhile, the deformation and strength fitting relationships with time of sandstone were also built. Furthermore, the dilatancy and volumetric recovery mechanical mechanisms of sandstone were revealed. The results showed that: 1) There were significant time-dependent evolution characteristics on the deformation and strength of sandstone;2) There were significant correlations among the internal friction angle, cohesion and the simulated depths;3) Volumetric recovery phenomenon of sandstone was observed for the first time, which mainly occurred at the simulated depth of 2000 m. The above research conclusions could provide a certain theoretical basis for the stability control of surrounding rocks in deep mines.
煤和岩石的时效力学行为往往很容易被忽略。为此,根据深部矿井围岩开挖前、开挖中和开挖后的全生命周期演化特征,基于初始高地应力状态恢复理论,对砂岩进行了“三阶段”三轴加卸载力学试验,获得了砂岩随时间变化的应力-应变曲线,构建了砂岩的变形和强度随时间的拟合关系,揭示了砂岩扩容和体积恢复的力学机制。结果表明:1)砂岩的变形与强度具有显著的时效演化特征;2)内摩擦角、内聚力与模拟深度具有显著的相关性;3)首次发现了砂岩的体积应变曲线出现“复容”现象,且该现象主要发生在模拟深度为2000 m处。上述研究结论可为深部矿井围岩稳定控制提供理论依据。
基金
Projects(52034009, 51974319) supported by the National Natural Science Foundation of China
Project(2020JCB01) supported by the Yue Qi Distinguished Scholar Project of China。
