卸荷条件下横观各向同性岩体扩容与能量特性分析

发布时间：2018-04-18 14:46

本文选题：石英云母片岩 + 横观各向同性　；参考：《岩土力学》2017年06期

【摘要】：丹巴水电站引水隧洞围岩主要为石英云母片岩,位于高应力区,层状特征显著,属于典型的横观各向同性岩体,其扩容和能量特性问题突出。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,研究三轴卸荷条件下石英云母片岩的扩容特性及能量变化规律。研究表明:(1)平行组与垂直组试件的特征应力均随围压的增大而增大,两者间具有良好的线性关系;(2)平行组试件裂纹闭合应力、损伤扩容应力及峰值应力均大于垂直组,起裂应力低于垂直组;(3)平行组试件扩容参数(扩容指标及剪胀角)大于垂直组,且随着围压的增大,两组试件扩容特征相继减弱,试件扩容指标与围压呈良好的指数型分布,特征剪胀角与偏应力比呈良好的线性分布;(4)平行组与垂直组试件峰值点和残余点处能量值均随围压增加而增大,且与围压呈良好指数型分布,相同围压下,平行组试件峰值点处能量特征值及残余可释放应变能均大于垂直组,残余耗散能低于垂直组;(5)无论是峰值点还是残余点处,两组试件耗散能量值与剪胀角以及能量特征值与扩容指标间均呈现良好指数型关系。
[Abstract]:The surrounding rock of the diversion tunnel of Danba Hydropower Station is mainly quartz mica schist, which is located in the high stress area and has obvious stratiform characteristics. It belongs to a typical transversely isotropic rock mass, and its expansion and energy characteristics are outstanding.Based on the MTS815 rock mechanics test platform, the expansion characteristics and energy variation of quartz mica schist under triaxial unloading are studied.The results show that the characteristic stress of parallel and vertical specimens increases with the increase of confining pressure, and there is a good linear relationship between them.The expansion parameters (expansion index and shear expansion angle) of parallel group specimen are larger than that of vertical group, and with the increase of confining pressure, the expansion characteristics of two groups of specimens are weakened one after another, and the expansion index and confining pressure of the specimen show a good exponential distribution.The energy values at peak point and residual point of parallel group and vertical group increase with the increase of confining pressure, and show a good exponential distribution with confining pressure, under the same confining pressure.The energy eigenvalue at peak point and residual releasing strain energy of parallel group are higher than that of vertical group, and the residual dissipation energy is lower than that of vertical group.There is a good exponential relationship between the dissipation energy value and the expansion angle, the energy characteristic value and the expansion index.
【作者单位】：四川大学水力学与山区河流开发保护国家重点实验室;四川大学水利水电学院;
【基金】：国家重点基础研究发展计划(973计划)(No.2015CB057903) 国家自然科学基金资助项目(No.51079092)~~
【分类号】：TV223

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