ISRM Suggested Method for Laboratory Determination of the Shear Strength of Rock Joints: Revised Version
ISRM Suggested Method for Laboratory Determination of the Shear Strength of Rock Joints: Revised Version
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DOI：
10.1007/s00603-013-0519-z
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发表时间：
2014-01-01
影响因子：
6.2
通讯作者：
Jiang Yujing
中科院分区：
文献类型：
--
作者：
Muralha, Jose;Grasselli, Giovanni;Jiang Yujing
“不连续”一词指的是岩体中抗拉强度可忽略不计的任何机械断裂（Priest 1993）。不连续可以是地质成因（如断层、层理、片理、解理面和叶理）或人为成因（如爆炸、应力或水力裂缝）。无论其起源如何，不连续面在岩体的行为中起着重要作用，因此，在涉及边坡，地表开挖和地下开口（如隧道或洞室）的一些岩石工程项目的行为中也起着重要作用。岩体中的不连续破坏是土木和采矿工程项目的主要危害，因为它会导致许多事故和昂贵的施工/生产延误。评估这些块状系统对特定工程造成的风险需要评估岩石不连续面的抗剪强度。抗剪强度的估计可以通过剪切试验得到。最佳的抗剪强度估计来自于现场直剪试验，因为它们固有地考虑了任何可能的尺度效应（Barla et al. 2011; Alonso et al. 2011）。然而，由于这种测试的持续时间和成本，通常的做法是在相对较小的不连续样品上进行实验室直接剪切测试。通常，直接剪切试验是在不连续面施加恒定的法向载荷的情况下进行的。虽然该边界条件适用于涉及近地表岩石块体滑动的一类工程问题（例如，岩质边坡稳定性和地表开挖稳定性），但也有一类问题在发生滑动时正应力可能不保持恒定。也就是说，任何时候，在滑动过程中（例如，在地下开挖周围），不连续面的扩张受到约束，滑动面上的正应力可能会发生变化。对于这类问题，常法向刚度边界条件更适合于直剪试验（Johnston and Lam 1989; Leichnitz 1985）。
The term ‘discontinuity’refers to any mechanical break in a rock mass with negligible tensile strength (Priest 1993). Discontinuities can be geologic in origin (ie, faults, bedding, schistosity, cleavage planes, and foliations) or anthropogenic in origin (ie, blast-induced, stress-induced, or hydraulic-induced fractures). Regardless of their origin, discontinuities play a significant role in the behavior of rock masses and, consequently, in the behavior of several rock engineering projects involving slopes, surface excavations and underground openings such as tunnels or caverns. Discontinuity-induced failures in rock masses are a major hazard in civil and mining engineering projects as they are responsible for many accidents and costly construction/production delays. Assessing the risk posed by these blocky systems to a particular project requires the evaluation of the shear strength of the rock discontinuities. Estimates of shear strength can be obtained through shear testing. The best shear strength estimates are obtained from in situ direct shear tests as they inherently account for any possible scale effect (Barla et al. 2011; Alonso et al. 2011). However, due to the duration and cost of such tests, it is common practice to perform laboratory direct shear tests on relatively small discontinuity samples instead. Conventionally, direct shear testing has been conducted with a constant normal load applied to the discontinuity plane. While this boundary condition is appropriate for a class of engineering problems involving the sliding of rock blocks near the ground surface (eg, rock slope stability and surface excavation stability), there is class of problems where the normal stress may not remain constant as sliding occurs. Namely, any time the dilation of a discontinuity is constrained while sliding (eg, around an underground excavation), the normal stress on the sliding surface may vary. For this class of problems, a constant normal stiffness boundary condition is more appropriate for direct shear testing (Johnston and Lam 1989; Leichnitz 1985).