Energy evolution mechanism and failure criteria of jointed surrounding rock under uniaxial compression

Abstract

The object of this article is to investigate the energy evolution mechanism and failure criteria of cross-jointed samples containing an opening during deformation and failure based on the uniaxial compression test and rock energy principle. The results show that the energy evolution characteristics of the samples correspond to a typical progressive damage mode. The peak total energy, peak elastic energy, and total input energy of the samples all first decrease and then increase with an increase of half of the included angle, reaching their minimum values when this angle is 45°, while the dissipated energy generally increases with this angle. The existence of the opening and cross joints can obviously weaken the energy storage capacity of the rock, and the change in the included angle of the cross joint has a great influence on the elastic energy ratio of the sample before the peak stress, which leads to some differences in the distribution laws of the input energy. The continuous change and the subsequent sharp change in the rate of change in the energy consumption ratio can be used as the criteria of the crack initiation and propagation and the unstable failure of the sample, respectively.

摘要

基于单轴加载试验和岩石能量原理, 研究了含孔洞交叉节理试样在变形破坏过程中的能量演化机制和破坏准则。结果表明, 试样的能量演化特征属于典型的损伤渐进破坏模式。试样的峰值点总能量、弹性能和破坏时输入的总能量均随着交叉节理半夹角的增加整体呈先减小后增大的趋势, 在半夹角为 45°时最小, 而耗散能随着半夹角的增加呈增大趋势。孔洞和交叉节理的存在明显削弱了岩石的储能能力, 节理夹角的变化对峰前的弹性能比例影响较大, 导致输入能量的分配规律存在一定差异。能量耗散比变化率的连续突变和随后的急剧突变可分别作为试样裂纹萌生与扩展以及失稳破坏的判据。