采空区下特厚煤层大采高综放采场压架机理研究

Based on the important issue of coal and rock instability disaster, such as abnormal pressure on support and roof water inrush, which seriously affect the safety in production of working face for extremely-thick coal seam under goaf by sub-level caving mining with high bottom cutting height, a exploratory thinking of active prevention and control the disaster through mine wastewater in-situ weakening main contra strata is proposed. The traditional coal and rock instability disasters research train of thought,which was from passive solution of technology such as improve the support strength and reduce recovery rate might be changed. First, the structure of overlying strata and coal strata and its movement laws, as the relationship between the support and surrounding rock (especially pressure abnormal occurrence such as support crushing) of working face for extremely-thick coal seam under different conditions of goaf and different coal-rock combinations by sub-level caving mining with high bottom cutting height will be studied, while its transfer law and deformation mechanism of instability will be analysised. From this, the prediction models of overlying strata and coal strata movement laws of working face for extremely-thick coal seam under goaf by sub-level caving mining with high bottom cutting height will be established, while the coal and rock instability and disaster control will be forecasted;then, the mechanism, engineering application method and reasonable process parameters of the active prevention and control the disaster by mine wastewater in-situ weakening main contra strata will be researched. At last, the prediction model will be tested and corrected. The basic research can provide theoretical basis and technical support for extremely-thick coal seam under goaf by sub-level caving mining with high bottom cutting height, which have important theoretical significance and academic value and application prospect.

针对采空区下特厚煤层大采高综放采场支架异常压力、顶板突水等煤岩失稳灾变严重影响安全生产这一重大问题，提出采空区废水原位弱化主控煤岩层并主动预防控制灾变的探索性思路，改变传统只从改变工艺(提高支护强度和降低回收率)等被动方法解决煤岩失稳灾害的研究思路。首先研究不同采空区下、不同煤岩组合方式下特厚煤层大采高综放开采的煤岩结构及其移动规律，由此分析其力学传递规律与失稳变形机理，进而研究支架围岩关系(寻求避免工作面压架的条件)；在此基础上，建立采空区下特厚煤层大采高综放煤岩移动变形规律的预测模型和煤岩失稳灾变原位控制模型，然后研究采空区废水原位弱化主控煤岩层并主动预防灾变的机理、工程应用方法及合理的工艺参数，最后检验和修正预测模型。该研究为特厚煤层大采高综放开采的基础性研究，可为采空区下特厚煤层大采高综放开采提供理论依据与技术支持，其成果具有重要的理论意义、学术价值和应用前景。

采空区下特厚煤层大采高综放采场支架异常压力、顶板突水等煤岩失稳灾变严重影响安全生产。采空区下特厚煤层大采高综放采场上覆岩层的结构将形成一种近似于浅埋深而又非浅埋深、似厚冲积层而又非厚冲积层的的结构，其采场覆岩结构有其自身的特殊性。为了解决这一问题，本项目以采空区下特厚煤层大采高综放采场压架机理为研究中心，通过理论分析、数值模拟、相似模拟和现场实测等方法开展研究工作，项目取得了如下创新性成果：（1）从层间岩层结构垮落是否对下层煤开采有直接影响的角度分析，将下层煤垮落带是否与上层煤采空区贯通作为近距离煤层的界限，认为斜沟8#煤采空区下55m处赋存的13#特厚煤层开采属于近距离煤层开采。（2）通过数值试验和相似模拟试验研究采空区下特厚煤层大采高综放开采顶煤顶板变形垮落特征及支架工作阻力变化规律，直观显示了顶板全厚切落式来压特征，研究了上覆岩层结构形式及力学传递机理与变形失稳条件，找到了上下采空区全厚切落压架的条件并建立了对应判断准则。（3）采用高精度微震监测技术结合矿山压力理论及现场实测的综合研究手段，对围岩活动规律和矿山压力分布规律进行了研究，形成了针对采空区下特厚煤层大采高综放面围岩运动的高精度微震监测实时追踪技术，分析了岩层的空间结构、液压支架的受力状态，提出并实施了具体的顶板控制方案，可为安全生产提供技术支撑。（4）提出采空区积水原位弱化关键煤岩层并主动预防控制灾变的探索性思路，改变传统只从改变工艺(提高支护强度和降低回收率)等被动方法解决煤岩失稳灾害的研究思路，提出了工程应用方法及合理的工艺参数。上述研究成果填补了我国采空区下特厚煤层采场矿压和顶板突水防治理论的一项空白，对特厚煤层安全高效开采具有重要意义。项目已出版专著1部，发表论文26篇，授权发明专利1项，另外申请了11项发明专利、有6篇EI期刊投稿论文。