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针对煤矿山保护煤柱留设问题,开展了不同宽高比的煤柱单轴压缩试验,引入损伤变量及损伤统计本构模型,探讨全应力-应变过程中损伤变量与应变之间的关系。采用定量分析方法,得出煤柱尺寸与损伤变量之间的演化规律,即损伤变量受煤柱宽高影响显著,随着宽度增大,高度减小,损伤变量值减小,峰值应力增大;在煤柱受力至破坏状态的过程中,当宽高比为2时,煤柱损伤变量所受影响较小。综合考虑破坏峰值和损伤变量之间的关系,煤柱留设宽高比等于2为留设煤柱的最佳比例,其对煤矿开采的保护作用较好。损伤变量随应变的增加呈初始损伤阶段、损伤线性增加段和损伤平稳段,但总体上损伤变量与应变之间呈非线性正指数关系。
Aiming at the problem of coal column protection in coal mines, uniaxial compression tests of pillars with different aspect ratios were carried out. Damage constants and statistical constitutive models of damage were introduced to investigate the relationship between damage variables and strain in the whole stress-strain process. Quantitative analysis method was used to derive the evolution law between the coal pillar size and the damage variable, that is, the damage variable was significantly affected by coal pillar width and height. As the width increased, the height decreased, the damage variable value decreased and the peak stress increased In the process of coal column stress to failure, when the aspect ratio is 2, the influence of coal column damage variables is less affected. Considering the relationship between the damage peak and the damage variable, the ratio of coal pillar left aspect ratio equal to 2 is the best ratio of coal pillar to be set aside, which has a good protective effect on coal mining. The damage variables showed the initial damage stage, the linear increase section and the stable section with the increase of strain. However, there was a nonlinear positive exponential relationship between the damage variable and the strain.