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随着中国煤炭开采深度逐渐加深,煤岩组合体的力学特性与应力–应变关系显得越来越重要。煤岩组合体的原生裂纹和煤岩体之间的界面对其力学性质有较大影响。为了探知裂纹和界面的影响,主要研究了轴向裂纹应变随应力、应变的演化特征,并基于工程应变和自然(真实)应变的概念,建立轴向裂纹闭合模型(axial crack closure model,简称ACCM)及轴向裂纹扩展模型(axial crack propagation model,简称ACPM),最后建立了峰前应力–应变关系模型。分析发现,轴向裂纹应变与轴向应变关系可分为4个阶段,即初始阶段、稳定阶段、缓慢增长阶段和快速增长阶段,轴向裂纹应变与轴向应力关系与之类似。轴向裂纹闭合模型、轴向裂纹扩展模型与峰前应力–应变模型均能够较好地与试验数据吻合,能够描述应力–应变关系的非线性特点。
With the deepening of coal mining in China, the mechanical properties and stress-strain relationship of coal-rock assemblages become more and more important. The primary cracks in the coal-rock assembly and the interface between the coal and rock mass have a great influence on the mechanical properties. In order to investigate the influence of cracks and interface, the evolution characteristics of axial crack strain with stress and strain are mainly studied. Based on the concept of engineering strain and natural (real) strain, an axial crack closure model (ACCM ) And axial crack propagation model (ACPM). Finally, a model of pre-peak stress-strain relationship was established. The analysis shows that the relationship between axial strain and axial strain can be divided into four stages, that is, the initial stage, the steady stage, the slow growth stage and the rapid growth stage. The relationship between axial strain and axial stress is similar. The axial crack closure model, the axial crack propagation model and the pre-peak stress-strain model are in good agreement with the experimental data to describe the nonlinear characteristics of the stress-strain relationship.