近距离煤柱下巷道围岩裂隙演化规律研究
Study on fracture evolution of surrounding roadway under close distance coal pillar
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摘要: 针对近距离煤层斜穿遗留煤柱巷道围岩大变形难题,基于登茂通矿地质条件,构建UDEC-Trigon数值模型,分析了距2#煤层区段煤柱中心0、10、20、30 m处巷道围岩变形破坏特征及裂隙演化规律;结果发现:掘进期间,距煤柱中心0 m,两帮变形破坏严重,两帮移近量达602 mm,呈对称分布,距煤柱中心10 m,两帮变形呈不对称分布;回采期间,巷道变形破坏程度显著加剧,距煤柱中心10 m,顶板结构易失稳破坏,变形具有不对称性,距煤柱中心20 m处,巷道顶底板变形严重,距煤柱中心30 m处变形破坏相对较小。研究表明:距2#煤层区段煤柱中心不同位置处巷道结构变形破坏呈显著差异性,围岩变形与裂隙发育呈正相关,小变形时以剪切裂隙发育为主,围岩失稳破坏伴随张拉裂隙快速增加。Abstract: Aiming at the problem of large deformation of surrounding rock of roadway with coal pillar in near coal seam, based on the geological conditions of Dengmaotong Mine, the UDEC-Trigon numerical model was constructed, and the deformation characteristics and fractures evolution of roadway surrounding rocks were analyzed at the coal pillar center 0 m, 10 m, 20 m and 30 m away from the 2# coal seam. The results showed that during the excavation, the deformation of two walls were serious and the deformation volume was up to 602 mm, which was symmetrically distributed, and the deformation of two walls was asymmetrically distributed, which was 10 m from the center of the coal pillar; during the mining, the deformation degree of roadway was significantly aggravated. It was 10 m away from the center of coal pillar, the roof was vulnerable to instability and failure, and the deformation had asymmetry, at 20 m from the coal pillar center, the deformation of roof and floor was serious, while the deformation at 30 m from the coal pillar center was relatively small. The study shows that the deformation of roadway are significantly different at different locations from the pillar center of 2# coal seam, and the deformation of surrounding rock is positively correlated with the development of fractures, when the deformation of the surrounding rock is small, the main factor is the development of shear fractures, and the instability of surrounding rocks is more likely to be accompanied by the rapid increase of tensile fractures.