区域隔水关键层采动破坏的突水致灾机理与防治研究

Abstract: Mining under the phreatic aquifer of shallow coal seam may lead to the disaster of water inrush and the destruction of environment, and the mining water tightness property is influenced by the state and thickness of clay, so study on the regional water tightness key strata stability is the key to research the water inrush. The project will use the theory of strata controlling, solid-liquid coupling theory, and the theory of rock-soil mechanics and so on to research the water resisting property and control relationship, the formation thickness and distribution of clay aquiclude, and mining effect of different strata in shallow coal seam. Then to reveal the regional water tightness key strata formation mechanism, build the mechanical model of the regional water tightness key strata, and perfect the solid-liquid coupling experiment of "overburden rock destruction- phreatic aquifer migration- regional water tightness key strata controlling". By research the water inrush mechanism of regional water tightness key strata to analysis the threat level of roof water inrush. Through the establishment of regional key aquifuge stability evaluation criterion, to determine the reasonable thickness of protection layer and the comprehensive evaluation of the mining-induced water tightness property. Through the establishment of roof water inrush forecast model, so as to improve the regional key aquifuge stability control theory and technology system of water control, and put forward the prevention and countermeasures of water inrush, to ensure the safety in production of coal mine.

浅煤层潜水下开采既可能导致突水灾害又会造成环境破坏，而粘土的状态和厚度影响隔水层的采动隔水性，研究区域隔水关键层的稳定性是研究突水的关键。课题拟采用岩层控制、固液耦合理论、土力学等理论,研究浅埋煤层不同地层组合关系的隔水性能及控制关系，包括隔水粘土层组成、厚度、稳定分布情况以及采动影响。揭示区域隔水关键层的形成机理，建立区域隔水关键层稳定性的力学模型，完善"覆岩破坏-潜水运移-区域隔水关键层的控制"的固液耦合模拟实验技术体系，研究区域隔水关键层采动破坏的突水机理，分析顶板水害威胁程度。建立区域隔水关键层稳定性的评价准则，确定隔水层合理的保护层厚度，综合评价其采动隔水稳定性。建立顶板突水预测预报模型，完善区域隔水关键层稳定性的控制理论技术体系，提出水灾害防治及对策系统，确保矿井安全生产。

项目在国家自然科学基金面上项目的资助下，对区域隔水关键层采动破坏的突水致灾机理与防治进行了系统深入的研究。完成了黄土和红土的力学实验测试及水理性质测试，根据岩土介质的弹性力学和水的流体力学相似条件，研发了流固耦合实验材料，材料具有良好的非亲水性，力学变形性能稳定，满足流固耦合相似模拟实验的要求。通过不同基岩层厚、粘土厚度、松散层厚度条件下的实验，掌握了上覆岩层的垮落规律及采动裂缝发展演化规律，分析了不同采高、基土比条件对于隔水层破坏的影响，以及隔水层破断后遇水弥合机理。基岩厚度在30～60m的土基型固液耦合相似模拟和数值模拟表明，隔水土层厚度与采高之比k≤4的条件下，隔水土层将发生不可恢复的破坏，工作面突水较严重；在4<k<15的条件下，隔水土层裂缝将会贯通，形成突水通道，但随着工作面的继续推进部分裂缝受到水平作用力将会愈合；在k≥15的条件下，隔水土层裂缝不会贯通，不能形成突水通道。进行了浅埋煤层顶板水灾害预警系统的研究，开发了监测预警系统软件。从地表汇水特征、含水层的富水性、隔水土层的隔水性、覆岩组合特征、开采扰动特征五个方面出发，建立了基于AHP-GRA耦合评价的浅埋煤层顶板突水预测模型，减少了人为主观判断的影响。通过模型预测了安山矿各突水危险点坐标位置，进行了韩家湾2405工作面顶板突水预测计算，得到上覆岩层导水裂缝带高度，提前设计防控方案，提出了在沟谷正下方留设合理尺寸防水煤柱的措施，预防了突水事故发生，确保矿井安全生产。