等向压缩及偏压加载下锦屏大理岩变形特性研究
发布时间：2019-06-07 08:58
【摘要】：以中国锦屏地下实验室工程T_(2b)大理岩为研究对象,开展了等向压缩(σ_1=σ_2=σ_3)试验及不同围压下的三轴偏压(σ_1-σ_3)加载试验,分析讨论了大理岩等向压缩体积变形特点、围压对峰后变形行为及峰前渐进性变形破坏过程的影响。试验结果表明:大理岩的等向压缩体积变形在不同围压范围内经历了一个线性-非线性-线性的变化过程。等向压缩体变曲线上存在一个拐点(敏感应力),该点的围压能在一定程度上反映其应力历史。偏压加载时峰后变形表现为脆性-半脆性-延性转化特征,峰值强度随围压变化与等向压缩体变曲线斜率发生变化的转换围压是一致的。围压对渐进性破坏过程各个阶段均会产生一定影响,除偏差闭合应力阈值外,其余各特征偏应力阈值均随围压近似呈线性增加关系。在等向压缩和偏压加载时出现了2次裂隙闭合过程。试验成果对进一步研究硬岩的变形破坏机制、防治深部地下工程灾害具有一定参考价值。
[Abstract]:Taking T2b marble, an underground laboratory project in Jinping, China, as the research object, the isoaxial compression (蟽 _ 1 = 蟽 _ 2 = 蟽 _ 3) test and the triaxial bias pressure (蟽 _ 1-蟽 _ 3) loading test under different confining pressures have been carried out. The deformation characteristics of marble under isoaxial compression volume and the influence of confining pressure on the deformation behavior after peak and the progressive deformation and failure process in front of peak are analyzed and discussed. The experimental results show that the isotropic compression volume deformation of marble goes through a linear-nonlinear-linear process in different confining pressure ranges. There is an inflection point (sensitive stress) on the isotropic compression curve, and the confining pressure energy of this point reflects its stress history to a certain extent. The post-peak deformation under bias loading is characterized by brittleness, semi-brittleness and ductile transformation, and the change of peak strength with the variation of confining pressure is consistent with the change of the slope of isotropic compression curve. The confining pressure has a certain influence on each stage of the progressive failure process. Except for the deviation closed stress threshold, the other characteristic bias stress threshold increases linearly with the confining pressure approximate. There are two fracture closure processes during isotropic compression and bias loading. The test results have certain reference value for further study of deformation and failure mechanism of hard rock and prevention and control of deep underground engineering disasters.
【作者单位】： 东北大学深部金属矿山安全开采教育部重点实验室;劳伦森大学工程学院;
【基金】：国家自然科学基金项目(No.11572083) 高等学校学科创新引智计划资助(No.B17009)~~
【分类号】：TU45
本文编号：2494675
[Abstract]:Taking T2b marble, an underground laboratory project in Jinping, China, as the research object, the isoaxial compression (蟽 _ 1 = 蟽 _ 2 = 蟽 _ 3) test and the triaxial bias pressure (蟽 _ 1-蟽 _ 3) loading test under different confining pressures have been carried out. The deformation characteristics of marble under isoaxial compression volume and the influence of confining pressure on the deformation behavior after peak and the progressive deformation and failure process in front of peak are analyzed and discussed. The experimental results show that the isotropic compression volume deformation of marble goes through a linear-nonlinear-linear process in different confining pressure ranges. There is an inflection point (sensitive stress) on the isotropic compression curve, and the confining pressure energy of this point reflects its stress history to a certain extent. The post-peak deformation under bias loading is characterized by brittleness, semi-brittleness and ductile transformation, and the change of peak strength with the variation of confining pressure is consistent with the change of the slope of isotropic compression curve. The confining pressure has a certain influence on each stage of the progressive failure process. Except for the deviation closed stress threshold, the other characteristic bias stress threshold increases linearly with the confining pressure approximate. There are two fracture closure processes during isotropic compression and bias loading. The test results have certain reference value for further study of deformation and failure mechanism of hard rock and prevention and control of deep underground engineering disasters.
【作者单位】： 东北大学深部金属矿山安全开采教育部重点实验室;劳伦森大学工程学院;
【基金】：国家自然科学基金项目(No.11572083) 高等学校学科创新引智计划资助(No.B17009)~~
【分类号】：TU45
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