“三下”急倾斜煤层充填长壁综采岩层控制及地表沉陷规律研究

The law of overlying strata movement and ground subsidence caused by mining steep coal seam under building, raiway and water bodies is more complex than mining gently inclined coal seam. It makes that large number of steeply inclined coal seam under buildings, raiways and water bodies is difficult to be efficient and safe mined. To solve this problem, a method combined comprehensive mechanized coal mining technique and cemented filling technique is expected to be the effective way. The common mechanism of the fully mechanized mining supporter and the roof and floor strata will be studied on condition that the goaf of fully-mechanized face is filled by cementing material. After the intervention of backfill, the formation and evolution law of three dimension stress in the stope wall rock in steep coal seam will be studied under the multi-factor synergistic effect of mining thickness, coal seam dip angle, roof and floor lithology and support performance. The mechanical process and stability of the "backfill-supporter-coal-rock" large structure in high-dipping and fully-mechanized face will be studied. The relationship of the large structure stability, overlying strata movement and surface deformation will be studied. On condition that the goaf is continuously filled by cementing material, the "backfill-supporter-coal- rock" large structure and its stability criterion in fully-mechanized face in steep seam will be put forward Controlling mechanism of the large structure stability to overlying strata movement and surface deformation will be revealed. It will lay a theoretical foundation for coming into being a scientific mining method, which can effectively protect surface buildings, ensure high recovery rate of resources and environmental safety when mining steep coal seam under buildings, raiways and water bodies.

"三下"急倾斜煤层开采引起的上覆岩层移动和地表沉陷规律比开采"三下"缓倾斜煤层时更具复杂性，使得大量"三下"急倾斜煤层难以高效、安全回采。采用采空区胶结充填的走向长壁综采是解决这一问题的可期待的有效途径。项目主要研究急倾斜煤层综采工作面在采空区充填条件下，支架与顶底板岩层共同作用机理；研究充填体介入后，开采厚度、煤层倾角、顶底板岩性、支架性能等多种因素协同作用下急倾斜煤层采场围岩三维应力场形成与演化规律；研究急倾斜煤层综采工作面"充填体-支架-煤体-围岩"采场大结构形成的力学过程和稳定性以及"大结构"稳定性与上覆岩层移动和地表变形的相关关系。提出急倾斜煤层综采工作面采空区胶结充填条件下"充填体-支架-煤体-围岩"形成采场大结构及稳定性判别准则，揭示"大结构"动态平衡对上覆岩层移动和地表变形控制机理，为形成有效保护地表构筑物、高资源回收率和安全环保的"三下"急倾斜煤层采矿方法奠定理论基础。

“三下”急倾斜煤层开采引起的上覆岩层移动和地表沉陷规律十分复杂，使得大量“三下”急倾斜煤层难以高效、安全回采。采用采空区胶结充填的走向长壁综采是解决这一问题的有效途径。项目围绕“三下”急倾斜煤层充填长壁综采岩层控制及地表沉陷规律，开发了多种适用于矿山充填的不同类型、不同性能充填材料：常规型煤矸石胶结充填材料、粘土型胶结充填材料和泡沫型煤矸石胶结充填材料等；研究了不同配比条件下充填材料的管道输送特性，以及固结后充填体在不同养护时间的力学性能；研究了早强剂与煤矸石泡沫料浆的相容性及其早强效果和煤矸石泡沫充填材料抗压强度影响因素；研制了以煤矸石为充填骨料的煤矿采空区充填用高泡沫稳定性发泡剂；自主开发建造了膏体自溜充填模拟试验系统、卧式多角度矿山开采平面相似模拟实验装置和急倾斜煤层充填开采的搪瓷溜槽管道装置各一套；提出了一种适用于急倾斜煤层综采充填的急倾斜煤层走向长壁综采胶结充填采煤法；提出了沿工作面倾向的胶结充填开采顶板模型和沿工作面走向的“煤体-支柱（架）-胶结体”联合作用下顶板超静定梁模型，给出了顶板岩梁及其两种特殊情况下的岩梁两端支座反力、两端弯矩和整个岩梁剪力、弯矩分布的表达式，给出了控顶距、充填体强度形成的速度、支柱（架）的支撑力、埋藏深度等主要因素对岩梁及其支座受力的影响规律；提出了充填开采的极限跨距、工作面极限推进速度和倾向极限长度三个新概念，并推导出了相应计算表达式，研究了岩梁厚度、控顶距、充填体早期抗压强度、充填体终期强度形成时间、岩梁抗压极限强度和抗剪极限强度等因素对极限推进速度大小的影响规律；研究了不同煤层倾角急倾斜煤层胶结充填开采矿压显现规律；以湖南某矿24采区地质资料为基础，研究了充填开采对地表变形的影响规律。研究成果为形成有效保护地表建（构）筑物、高效率和安全环保的“三下”急倾斜煤层采矿方法奠定了一定的理论基础。