Breakage and shear behaviour of intermittent rock joints
Breakage and shear behaviour of intermittent rock joints
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DOI：
10.1016/s1365-1609(03)00060-1
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发表时间：
2003-07-01
影响因子：
7.2
通讯作者：
Kutter, HK
中科院分区：
文献类型：
--
作者：
Gehle, C;Kutter, HK
本文用一种专门设计的新型剪切装置，对断续节理的破坏和剪切特性进行了一系列直剪试验研究。试验分别在类岩石材料或硬岩石试件上进行，试件中含有理想化的非持久性节理，这些节理由若干沿中心剪切轴沿着呈雁列排列的短裂纹组成，发现这种节理群的剪切特性由不同的相组成。剪切的第一阶段是实际断裂的阶段，由翼裂纹的形成开始，从现有的裂纹开始并增长到材料桥中，并由连接翼裂纹之间的区域中的初始裂纹的额外的新裂纹的产生结束。剪切的第二阶段是以摩擦过程为特征的，在当时的连续剪切带中体积增加。最后，第三阶段的剪切，达到大的剪切位移后，是由滑动过程中的强烈破裂剪切带。在大量的剪切试验中，不连续节理的几何参数以及加载条件已被发现影响激活的抗剪强度在每个阶段的剪切显着不同的程度。初始裂纹的方向和正应力，然而，已被确定为最有影响力的参数。根据试验条件的不同，一个初始不连续的岩石节理不仅在破裂前，而且在随后的两个剪切阶段中的一个阶段都能激活最大的剪切阻力，控制不同剪切阶段的机制可以确定为：（1）拉伸破裂，（2）塑性节理区的滚动和滑动摩擦，（3）在角砾质材料组成的节理充填物中的滑动。(C)2003 Elsevier Ltd.保留所有权利。
The breakage and shear behaviour of intermittent rock joints have been investigated in a series of direct shear tests with a new shear device, specifically designed for this purpose. The tests have been performed on specimens of rock-like material or hard rock, respectively, incorporating idealized non-persistent joints, made up of a number of short cracks in an en-echelon arrangement along the central shear axis.The shear behaviour of such a joint constellation has been found to be composed of different phases. The first phase of shearing is that of the actual rupture, initiated by the formation of wing cracks, starting from the existing cracks and growing into the material bridges, and concluded by the generation of additional new fractures connecting the initial cracks in the zone between the wing cracks. The second phase of shearing is characterized by friction processes and volume increase in the then continuous shear zone. Finally, the third phase of shearing, reached after large shear displacements, is determined by sliding processes inside the strongly fractured shear zone.In a large number of shear tests the geometrical parameters of the discontinuous joints as well as the loading conditions have been found to influence the activated shear resistance in each phase of shearing to a noticeably different extent. The orientation of the initial cracks and the normal stress, however, have been identified as the most influential parameters. Depending on the test conditions, an initially discontinuous rock joint can activate the largest shear resistance not just before rupture but in one of the two subsequent phases of shearing as well.The mechanisms which govern the different shear phases could be identified as (1) tensile rupturing, (2) rolling and sliding friction of dilatant joint zones and (3) sliding within the joint filling composed of brecciated material. (C) 2003 Elsevier Ltd. All rights reserved.