结构面爬坡剪断耦合作用影响因子与影响规律

为研究硬性结构面剪切过程中爬坡剪断耦合作用，制作了不同高度h和坡度 组合的凸起体的硬性结构面三维模 型，开展模型剪切试验，试验结果证实了两种作用的耦合。分析剪切运动特征，提出了利用剪断面积Sj与剪切面积S的比值K定量表征爬坡和剪断耦合程度，在不同的主导作用下K值变化在0～1之间，并建立了考虑爬坡剪断耦合作用的抗剪强度算式，可评价锯齿型硬性结构面抗剪强度影响规律，得出抗压强度大的硬岩、表面起伏较平缓的结构面K值小，爬坡摩擦对抗剪强度贡献的组分大；抗压强度小的软岩、表面起伏较大的结构面K值大，岩石材料的强度对抗剪强度贡献的组分大。

Impact factors and influence law of joint overriding and cutting off coupling effect

In order to study overriding and cutting off coupling effect in process of joint shear, the joint three-dimensional models which have asperities of different combinations of height (h) and angle (?) are made for, conducting model shear tests. The test results confirm this coupling effect. The joint shear movement characteristics are analyzed; and a ratio of cutting off area Sj to shear area S, i.e. K, is proposed to present quantitative characteristics for the degree of coupling effect. In different dominant effect, the K changes between 0-1. Meanwhile, a shear strength formula which is involved in the coupling effect of overriding and cutting off is established to help valuating effect rule of joint shear strength. The results show not only that shear strength is largely determined by overriding friction when the K is low for hard rock with large compressive strength and for slightly undulated joint surface, but also that it is largely determined by strength of the rock material when the K is high for soft rock with small compressive strength and for roughly undulated joint surface.