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岩石是一种含有多裂纹的高度非均匀材料 ,其变形破坏过程实质上是岩石材料中裂纹的萌生、扩展、相互作用直至最后贯通破坏的动态演化过程。考虑非均匀性影响的岩石多裂纹扩展中相互作用及其贯通破坏机制研究是岩石断裂力学的重要研究课题 ,同时也对裂隙岩体开挖工程稳定性、边坡滑坡预防及构造地震产生机制及预测预报等研究具有重要的理论和实际意义。本文主要通过自主开发的基于岩石细观损伤模型的二维岩石破裂过程分析软件RFPA2D并辅以一定的相似材料试验 ,结合已有的研究成果对岩石多裂纹的破坏机制进行了分析 ,探讨了岩石中预置裂纹的空间排布几何特征、力学参数、加载方式和非均匀因素等对其演化过程中的应力场分布、声发射分布、岩桥区的贯通模式及贯通准则的影响。通过上述研究取得了如下主要认识 :(1)多裂纹相互作用主要表现为应力场的相互扰动。根据裂纹的相对几何位置和加载方式等条件 ,进行不同叠加后的应力场可产生两种效应 ,即相互增强或减弱效应。裂纹相互作用的应力场叠加强度和应力属性决定了裂纹扩展和贯通的基本模式。由于岩石的抗拉强度较之抗压强度小一个数量级左右 ,因而裂纹的萌生总是首先出现于预置裂纹端部拉应力集中区 ,产生拉 张性质的翼形裂纹 ,随着裂纹的扩展 ,裂纹尖端的?
Rock is a highly inhomogeneous material with many cracks. Its deformation and failure process is essentially the initiation, propagation and interaction of cracks in the rock material until the dynamic evolution of the final through failure. The research on the interaction and its failure mechanism in multi-crack propagation of rock considering the influence of inhomogeneity is an important research topic in rock fracture mechanics. At the same time, it also analyzes the stability of rock excavation, the prevention of slope landslide and the mechanism of tectonic earthquake Prediction and other research has important theoretical and practical significance. In this paper, we mainly analyze the failure mechanism of multi-cracks in rock by the independently developed rock-fracture analysis software RFPA2D based on meso-damage model of rock and assisted by some similar material tests, The influence of geometric characteristics, mechanical parameters, loading methods and non-uniform factors on the distribution of stress field, acoustic emission distribution, penetrating mode of rockfill area and penetration criterion in the evolutionary process are presented. The main findings obtained from the above studies are as follows: (1) Multi-crack interaction is mainly manifested as mutual perturbation of stress field. According to the relative geometric location of cracks and loading conditions, the stress field after different superposition can produce two kinds of effects, that is, strengthen or weaken each other. The stress field superposition strength and stress properties of the crack interaction determine the basic mode of crack propagation and penetration. Since the tensile strength of rock is about one order of magnitude smaller than its compressive strength, the initiation of cracks always occurs first in the tensile stress concentration zone at the tip of the pre-crack, resulting in the tensile crack of wing shape. As the crack propagates, Crack tip?