Numerical simulation of a direct shear test on a rock joint using a bonded-particle model
Numerical simulation of a direct shear test on a rock joint using a bonded-particle model
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DOI：
10.1016/j.ijrmms.2009.03.007
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发表时间：
2009-12-01
影响因子：
7.2
通讯作者：
Song, Jae-Joon
中科院分区：
文献类型：
--
作者：
Park, Jung-Wook;Song, Jae-Joon
对岩石节理进行了数值模拟，并使用PFC3D进行了一系列广泛的直剪试验。验证了用接触黏结模型模拟岩石节理的可行性，并考察了节理的几何特征和微观特性对其剪切行为的影响。从微裂纹和接触力分布、剪切方向和法向应力和位移等方面观察了材料的粗糙破坏。通过定义节理表面上的节理接触，在完整试样上得到了节理粗糙系数（JRC）在10 ~ 20之间的粗糙节理。为了模拟由风化和变化引起的节理壁强度（JCS）的降低，参与节理接触的颗粒之间的结合强度降低了高达70%。在给定应力下的剪切行为和破坏过程与实验室试验中观察到的结果吻合良好。摩擦系数是影响抗剪强度和剪胀角的最重要因素。接头粗糙度和接触结合强度的变化对黏聚力的影响大于峰值摩擦角的影响。此外，还提出了一种新的表示关节JRC和JCS值的方法，以供实际应用。采用数值三维扫描技术对模拟接头的实际JRC进行了评估，并研究了JCS与接触结合强度的关系。2009爱思唯尔有限公司版权所有。
Rock joints were numerically simulated, and an extensive series of direct shear tests were carried out using the code PFC3D. The feasibility of reproducing a rock joint using the contact bond model was demonstrated, and the effects of the geometrical features and the micro-properties of a joint on its shear behavior were examined. Asperity failure was observed from the micro-cracks and contact force distribution, as well as the stresses and displacements in shear and normal directions. A rough joint with a joint roughness coefficient (JRC) value ranging from 10 to 20 was produced in an intact sample by defining the joint-contacts along a predefined joint surface. To simulate a decrease in joint wall strength (JCS) caused by weathering and alterations, the bond strength between particles involved in the joint-contacts was reduced by up to 70%. The shear behavior and failure progress at a given stress corresponded well to those observed in laboratory tests. The friction coefficient was the most important factor governing the shear strength and dilation angle. The variation in joint roughness and contact bond strength had a larger effect on the cohesion than peak friction angle. In addition, a new approach to represent JRC and JCS values of a joint was proposed for practical use. A numerical 3D-profile scanning technique was developed to evaluate the actual JRC of the simulated joint, and the relationship between the JCS and the contact bond strength was investigated. (C) 2009 Elsevier Ltd. All rights reserved.