Table4_Study on the mechanism of coal pillar breaking and fracture development under repeated mining in a close seam group.XLSX

The study show the influence of coal mining on pillar under a repeated mining, in a close coal seam group, the fracture and instability process and influence mechanism of fracture development on the oxidation of coal pillars. In this paper, FLAC3D numerical simulation software is used to simulate the dynamic evolution characteristics of stress, displacement of the upper coal pillar. The results show that 1) The theoretical length of the fracture along the strike of the upper coal pillar is obtained by establishing the mechanical model of the upper coal pillar, which is consistent with the numerical simulation results. 3) In this paper, according to the dynamic evolution characteristics of displacement and stress on the coal pillar, the coal pillar is divided into the “step subsidence area”, “fracture compaction area” and “reverse stress area”, and the high risk area of the coal spontaneous combustion is determined.

本研究揭示了在重复开采条件下，煤炭开采对近距离煤层组中煤柱的影响，以及煤柱的断裂和失稳过程及其对煤柱氧化作用的机理。本文采用 FLAC3D 数值模拟软件模拟了上煤柱的应力、位移动态演化特征。研究结果表明：1）通过建立上煤柱的力学模型，获得了沿上煤柱走向的断裂理论长度，与数值模拟结果相吻合。3）基于煤柱的位移和应力动态演化特征，本文将煤柱划分为‘阶梯式下沉区’、‘断裂压实区’和‘反向应力区’，并确定了煤自燃高风险区域。