论完整岩体的现场强度

发布时间：2018-01-15 08:19

本文关键词：论完整岩体的现场强度　出处：《岩石力学与工程学报》2014年01期 　论文类型：期刊论文

【摘要】：目前国际上普遍认为完整岩体的现场强度近似等于(0.4?0.1)?c,其中,?c为室内岩石单轴抗压强度。此外,也有学者建议原位岩体的破坏强度,即地下工程围岩的启裂强度,可等价于室内单轴压缩试验或现场微震监测确定的岩石裂隙初始的应力;其原理主要以基于Kirsch解析解或简化的数值模拟(光滑的开挖边界)来近似表达隧道开挖面上的最大切向应力?max。然而,这些方法均忽略了开挖边界的几何非规则性对计算结果的影响。经论证表明,若考虑开挖面的几何非规则性因素,完整岩体的现场破坏强度并不等于(0.4?0.1)?c,其破坏强度可高达(0.8?0.05)?c。以加拿大地下实验室Mine-by试验隧道为例,并以该隧道的实际断面形状为几何边界条件,采用有限元软件Phase 2模拟隧道围岩的渐进破坏过程。研究结果表明,当原位岩体强度为0.8?c时,模拟结果与实际观测结果具有很好的一致性。因此,忽略开挖边界的几何非规则性而解读的原位岩体强度(0.4?0.1)?c仅是"等价"强度值,其低估了岩体的实际强度。
[Abstract]:At present, it is generally considered that the field strength of the intact rock mass is approximately equal to 0.4? 0.1? C, in which? C is the uniaxial compressive strength of indoor rock. In addition, some scholars suggest the failure strength of in-situ rock mass, that is, the fracture strength of surrounding rock in underground engineering. It can be equivalent to the initial stress of rock fracture determined by indoor uniaxial compression test or field microseismic monitoring. The principle is mainly based on the Kirsch analytic solution or simplified numerical simulation (smooth excavation boundary) to approximate the maximum tangential stress on the excavation surface of the tunnel. However, these methods ignore the influence of the geometric irregularity of the excavation boundary on the calculation results. It is demonstrated that the geometric irregularity of the excavated surface is taken into account. The in-situ failure strength of intact rock mass is not equal to 0.4? 0.1? C, its damage intensity can be as high as 0.8? 0.05? C. take the Mine-by test tunnel of the Canadian underground laboratory as an example, and take the actual section shape of the tunnel as the geometric boundary condition. The progressive failure process of surrounding rock of tunnel is simulated by finite element software Phase 2. The results show that when the strength of in-situ rock mass is 0.8? C, the simulated results are in good agreement with the observed results. Therefore, the strength of in-situ rock mass interpreted by neglecting the geometric irregularity of the excavation boundary is 0.4? 0.1? C is only "equivalent" strength value, which underestimates the actual strength of rock mass.
【作者单位】：劳伦森大学工程学院;核工业北京地质研究院;卓越开采创新中心;
【基金】：加拿大国家自然科学与工程研究基金项目(418932 11) 国家自然科学基金资助项目(11102061)
【分类号】：TU45
【正文快照】： 1引言劈裂破坏(spalling failure)是硬岩地下工程开挖边界附近的典型脆性破坏现象,即围岩在高应力作用下显现的张拉性破裂行为。合理地确定完整或节理岩体的原位强度是国际岩石力学与工程领域最具挑战性的课题之一。由于实际操作困难,不可能进行开挖尺度的力学试验以确定其强

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