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为揭示石英云母片岩变形及能量特征,针对平行片理和垂直片理方向的试件,基于MTS815岩石力学试验平台开展不同围压下的卸荷试验,分别从体积变形系数、能量比、能量变化率、能量应力增量比等方面系统研究高围压卸荷条件下石英云母片岩变形破坏特征及能量演化规律。结果表明:平行组试件径向变形发育能力及各特征应力量值均高于垂直组;其能量演化规律具有显著的围压效应,2组试件能量特性差异明显;与垂直组相比,平行组试件峰前、峰后应变能变化率较低且高围压下裂隙发育及塑性变形程度更高;提出能量应力增量比以表征试件能量变化对卸荷程度的敏感性,2组试件峰前能量应力增量比均随围压的增加而增加,但峰后弹性能应力增量比几乎不受初始围压的影响,垂直组峰前、峰后弹性能应力增量比和耗散能应力增量比量值均大于平行组。
In order to reveal the deformation and energy characteristics of quartz mica schist, the unloading tests under different confining pressures were carried out based on the MTS815 rock mechanics test platform for the specimens with parallel and vertical direction. The parameters of deformation, energy ratio, energy change Rate and ratio of energy and stress increment, the deformation and failure characteristics of quartz mica schist and evolution of energy under high confining pressure and unloading conditions are studied systematically. The results show that the ability of radial deformation and stress of parallel specimens are higher than that of vertical specimens. The energy evolution law has significant confining pressure effect. The energy characteristics of two specimens are obviously different. Compared with vertical group, The rate of change of strain energy before and after peak is lower and the fracture development and plastic deformation under higher confining pressure are higher. The energy stress increment ratio is proposed to characterize the sensitivity of specimen energy change to unloading degree. 2 The peak energy increment before and after the peak stress of the specimens increased with the increase of the confining pressure. However, the post-peak post-peak elastic stress increment ratio was hardly affected by the initial confining pressure. And dissipated energy stress increment than the value of the parallel group.