不整合地层下煤层开采覆岩裂隙场发育特征-IngentaConnect.PDF

摇 第36卷第11期 煤摇 摇 炭摇 摇 学摇 摇 报 Vol.36摇 No.11摇 摇 2011年 11月 JOURNAL OF CHINA COAL SOCIETY Nov.摇 2011摇 摇 摇 文章编号:0253-9993(2011)11-1795-06 不整合地层下煤层开采覆岩裂隙场发育特征 张摇 燕,纪洪广,王金安 (北京科技大学 土木与环境工程学院,北京摇 100083) 摘摇 要:以宁夏石嘴山矿西区3号煤层开采为工程背景,采用相似模型试验、数值模拟计算,研究深 部不整合覆岩下煤层开采所引起的裂隙发育特征,并对两种方法分别得到的裂隙带形态进行对比 分析。 由于煤系地层与上覆地层不整合,开采扰动后应力重分布及覆岩裂隙发育具有其特殊性。 研究发现:煤层开采过程中,采空区周围出现“应力拱冶;地层不整合面的存在阻隔了煤层开挖引起 的应力重分布时的应力传递,使开采扰动后主应力在不整合面下方局部呈现应力集中现象,从而使 不整合面下方附近岩体的破坏程度加剧,使裂隙带最终形态为“左高右低冶的非对称“马鞍形冶。 关键词:不整合地层;深部煤层开采;覆岩裂隙;应力拱;UDEC 中图分类号:TD325郾1摇 摇 摇 文献标志码:A Fracture development due to coal mining under unconformable overlying strata ZHANG Yan,JI Hong鄄guang,WANGJin鄄an (School of Civil and Environmental Engineering,University of Science and Technology Beijing,Beijing摇 100083,China) Abstract:The development characteristics of fractures due to coal mining under deep unconformable overlying strata wasinvestigatedusingthe similar model test and DEMnumerical simulation,andtaking No郾3 coal seam of Shizuishan in Ningxia Province as the engineering background.The comparison was performed between the results obtained from the similar model test andthe DEMnumerical simulation.It isrealizedthat the development of fracture andtheredis鄄 tribution of stresses in overlying rock mass are both unique due to the unconformity between the coal strata and the overlying strata.It isfound that the stress arch appears over the goaf in the overlying rock mass in the process of coal mining.The transmission of stresses is blocked by the unconformity of strata during the process of stresses redistribu鄄 tion induced by coal mining.That results in that the principle stresses concentrate at some local regions beneath the unconformity.Thestressesconcentr