基于Schwarz交替法求解分析浅埋近距离煤层开采覆岩结构演化规律  

Evolution rule of overlying strata structure in repeat mining of shallow close distance seams based on Schwarz alternating procedure

作　　者：李磊[1,2,3] 李寿君[4] LI Lei;LI Shoujun(China Coal Research Institute,Beijing 100013,China;Coal Minging&Designing Department,Tiandi Science&Technology Co.,Ltd.,Beijing 100013,China;CCTEG Coal Mining Research Institute,Beijing 100013,China;Zhalainuoer Coal Industry Co.,Ltd.,Manzhouli 021412,China)

机构地区：[1]煤炭科学研究总院,北京100013 [2]天地科技股份有限公司开采设计事业部,北京100013 [3]中煤科工开采研究院有限公司,北京100013 [4]扎赉诺尔煤业有限责任公司,内蒙古满洲里021412

出　　处：《采矿与岩层控制工程学报》2021年第2期27-37,共11页Journal of Mining and Strata Control Engineering

基　　金：华能集团总部科技基金资助项目(HNMYKJ19-12);天地科技股份有限公司开采事业部科技创新基金资助项目(KJ-2019-TDKCMS-02)。

摘　　要：我国西部地区有着丰富的浅埋近距离赋存条件的煤炭资源,其特点是煤层埋藏较浅,上覆基岩厚度较薄,覆盖层为含水砂层。该类型矿井工作面开采一旦波及到含水砂层,工作面将产生涌水溃砂等灾害事故。为了预防此类矿山灾害问题,通过弹性力学和复变函数理论建立了近距离煤层开采扰动的"无限平面双矩形孔口"理论力学模型,并对其覆岩结构演化规律进行了深入研究。主要研究结果为:(1)基于弹性力学和Schwarz交替法推导了煤层重复开采扰动覆岩应力场理论公式,并采用理论解析方法对不同中间岩层厚度下覆岩应力场分布规律和破坏范围进行了分析研究。研究表明:覆岩内水平应力σx整体呈"X"型分布,顶底板岩层处于拉应力状态,左右两侧呈椭圆形分布;当中间岩层厚度为20 m时,工作面上方岩层处于拉应力状态,极值拉应力为0.82 MPa,覆岩破坏区达到58 m。与上煤层开采引起的32 m裂缝带高度相比,下煤层开采引起的覆岩破坏范围明显增大;(2)灵露煤矿Ⅱ2-1和Ⅱ3煤层开采相似材料模拟结果表明:整个中间岩层发生破坏,与上煤层开采引起的35 m裂缝带高度相比,下煤层开采引起的裂缝带发育高度明显增大,达到61 m。下煤层采动造成了原上覆岩层裂缝带的二次发育。相似材料模拟试验验证了该理论解析方法的可行性。研究成果对浅埋煤层安全高效开采和可持续性发展具有一定的理论指导意义。There is a type of shallow close distance seams in Western China,which is buried shallow,has thin rock overlying strata and water-bearing sand seam.Under the geological conditions and mining technology of shallow close distance seams,once the water-bearing sand seam is affected by the coal face mining,water and sand pouring disaster will occur,which affects the safety and production of the coal mine.In order to avoid water and sand pouring problems of overlying strata structure in repeat mining of shallow close distance seams,a new theoretical approach is proposed to build up the double-rectangular-hole theoretical model within infinite plane to analyze the evolution rule of overlying strata structure in repeat mining of shallow close distance seams,and carried out similar material simulation.Firstly,based on elastic theory and Schwarz alternating procedure,a theoretical formula of stress field of overlying strata is deducted.Based on this theoretical model,the evolution rule of stress field in overlying strata of upper-lower coal seams and failure range is evaluated.The research results show that the horizontal stress distribution in overlying strataσ_x is X-shaped,the floor and roof of the coal face is under tensile stress.When the intermediate rock is 20 m in thickness,the maximum tensile stress is up to 0.82 MPa,the failure zone is up to 58 m.Compared with the failure zone of 32 m in the mining of single coal seam,the failure zone increases.Secondly,the similar material simulation test results show that,the whole intermediate rock seams fails.Compared with the failure zone of 35 m in the mining of upper coal seam,the lower coal seam induces the increase of the failure zone,up to 61 m,namely,the mining of lower coal seam increases the original failure zone induced by upper coal seam.The similar material simulation tests prove the theoretical approach is good.The research results provide theoretical basis and technical support for the repeat mining of shallow close distance seams in Western China.

关 键 词：近距离煤层 覆岩结构 理论解析 平面双矩形孔口模型 SCHWARZ交替法 

分 类 号：TD821[矿业工程—煤矿开采]