厚煤层高强度开采覆岩“两带”模式形成机理研究

The damages of the overlying strata and surface, which caused by the longwall high-intensity mining in thick coal seam, are more serious. The fractured zone in overburden strata may directly connect to the surface or the overburden strata cracks may cut through the surface cracks. The “two zone” damage mode, which includes caved zone and fractured zone formed in overburden strata, will result in surface ecological environment damage and some production safety problems, such as gushing water, air leakage, inrush of sand, shields broken and etc. By means of site investigation, on-site observation and detection, indoor simulation experiment, theoretical analysis and its combination methods, the main key factors of influencing the overburden strata and surface damage will be analyzed in this project. The evolution characteristics of overlying strata damage and the calculation methods of “two zone” height will be studied. The surface discontinuous damages characteristics and the depth of surface cracks under high-intensity mining in thick seam will be also studied. The structural model of the overlying strata and surface damage was developed due to high intensity mining. And then the forming mechanism and forming conditions of the “two zone” damage mode in overlying strata due to thick seam high-intensity mining will be revealed. The research results will provide theoretical foundation and technical basis for the safe and efficient production of modern coal mines, preventing or mitigating mining damages, protecting the ecological environment of the surface and etc.

厚煤层长壁高强度开采造成的上覆岩层与地表破坏更为严重，上覆岩层内裂缝带可能直通地表或者覆岩裂缝与地表裂缝相贯通，在覆岩中形成垮落带、裂缝带的“两带”破坏模式，造成工作面涌水、漏风、溃砂、压架等生产安全问题及地表生态环境破坏问题。本项目通过现场调研、现场观（探）测、室内模拟实验和理论分析等相结合的研究方法，在分析高强度开采覆岩与地表破坏规律主控因素的基础上，研究厚煤层高强度开采上覆岩层破坏演化特征、“两带”破坏高度及其计算方法，研究高强度开采地表非连续破坏特征及地表裂缝深度，建立厚煤层高强度开采覆岩与地表破坏结构模型，揭示浅埋厚煤层高强度开采覆岩“两带”破坏模式形成的机理和形成条件。研究成果为现代化煤矿安全高效绿色开采、预防或减轻采动损害、保护地表生态环境等提供理论基础和技术依据。

厚煤层开采是我国现代化矿井生产的主流模式，而厚煤层高强度开采造成的覆岩破坏与地表生态环境恶化严重阻碍了绿色开采与生态文明建设进程，已成为制约矿区可持续发展与建设绿色矿山的关键技术难题。本项目以我国典型的厚煤层高强度开采煤矿为研究区，系统研究了厚煤层高强度开采覆岩“两带”破坏模式形成机理，结论如下：.（1）高强度开采内涵及指标体系与覆岩破坏充分采动程度定义及判别方法。结合我国厚煤层高强度开采现状，基于“采矿技术指标”+“负外部性”，科学界定了高强度开采的定义及8个主要技术特征，从地质采矿技术及采动影响破坏视角，构建了12项高强度开采判别指标体系。基于厚煤层开采覆岩破坏特征，提出了覆岩破坏充分采动程度的定义，给出了以二维“梯形-面积”、三维“四棱台-体积”为依据的覆岩采动程度判别方法，明确了覆岩破坏充分采动程度的主要影响因素。.（2）厚煤层高强度开采覆岩破坏特征及含水层失稳致灾机理。构建了工作面长度方向的压力拱结构模型，分析了覆岩破坏的突发性和阶段性等特征，阐明了厚煤层开采覆岩破坏传导过程，提出了采动覆岩破坏的“π”形模式，分析了工作面覆岩采动裂隙的发育规律，提出了基于量纲分析与覆岩破坏传递理论的导水裂缝带高度预测方法，揭示了采动影响下覆岩含水层破坏致灾机制。.（3）采动地裂缝发育规律及覆岩“两带”模式形成机理。研究了关键层对压力拱发育的影响，构建了从煤层开采到地表破坏的“三位一体”结构模型，分析了厚煤层高强度开采地表响应特征，阐明了采动影响下地表沉陷演化规律，揭示了采动地裂缝形成机制，构建了不同类型的采动地裂缝预测模型，结合覆岩采动裂隙演化规律，揭示了厚煤层高强度开采覆岩“两带”破坏模式形成机理。.（4）厚煤层高强度开采源头减沉控损技术。统筹煤炭绿色开采与水资源保护，研发了水体下厚煤层开采突水致灾源头防控技术体系，对推动我国绿色矿山建设与生态高质量发展具有重要意义。