大水矿井注浆堵水帷幕微震活动规律及其失稳机理研究

It is a basic guarantee for taking reasonable control measures to study the stability and early warning method of grouting curtain in the water-rich mine, up to now, the microfracture precursory characteristics during the preparation process of water inrush disaster induced by curtain instability still need to be researched scientifically, deeply and systematically, especially lacking of the evaluation index and early warning model for describing quantitatively the risk of curtain instability is established based on microseismic parameters. Based on this idea, the microseismicity induced by mining effect and hydraulic gradient disturbance stress is a precursor to the essential characteristics of water inrush disaster induced by curtain instability, the project break the traditional thinking to forecast the risk of water inrush disaster according to the apparent information about water pressure, water quantity and water temperature in curtain area, combined with the mechanical parameters during deformation and fracture of coal-rock in curtain area, the intrinsic motivation and microfracture precursors law nurtured by water inrush disaster induced by curtain instability is revealed by using of the physical experimental and numerical simulation method; then practical grouting curtains are employed as the background models. by means of microseismic monitoring technique, the microseismicity evolution law during the process of curtain instability is sought; and combining the mathematical statistics, the evaluation index and early warning model will be established for the risk of curtain instability, which can provide a theoretical basis for the establishment of operational disaster monitoring and early warning method for the water inrush disaster of curtain bodies based on the characteristics of microseismic parameters.

大水矿井注浆堵水帷幕稳定性和预警方法的研究是采取合理防治措施的根本保证，而目前尚需要科学、深入、系统地研究采动与高水压下帷幕失稳诱发突水灾害孕育过程的内在动因和微破裂前兆特征，尤其是在基于微震参数建立定量描述帷幕失稳危险性的评价指标与预警模型方面还需要进一步研究。本项目基于"开采效应和水力梯度应力扰动诱发微震活动性是帷幕失稳诱发突水灾害前兆本质特征"这一学术思路，突破以帷幕区域水压、水量及水温等表观信息监测为依据进行突水灾害预测的传统思路，以帷幕区域煤岩变形破坏过程中的力学参数为基础，采用物理实验与数值模拟方法，揭示帷幕失稳诱发突水灾害孕育的内在动因和微破裂前兆规律；以实际的堵水帷幕为背景工程，借助于微震技术，探寻帷幕失稳过程中的微震活动性演化规律；结合数理统计方法，并基于微震参数特点建立帷幕失稳危险性预警的评价指标及预警模型，为建立可操作性的帷幕突水灾害监测预警方法的研究提供理论依据。

矿井注浆堵水帷幕的稳定性直接关系到矿井发生突水灾害事故的危险性，因此有必要对大水矿井注浆堵水帷幕的稳定性及其失稳机理进行深入系统的研究。本项目通过对注浆帷幕区域裂隙煤岩进行三轴循环加卸载声发射试验，研究了帷幕区域单结构面煤岩体的强度、变形特性、破坏形式和声发射特征受结构面长度和角度变化的影响规律，揭示了帷幕区域裂隙煤岩的变形破坏机制及前兆规律；通过对注浆帷幕体进行受力破坏过程渗透特性试验，研究了注浆帷幕体在高水头压力和开采扰动综合作用下的变形破坏机制及渗透特性；利用岩石破裂过程分析(RFPA)系统，通过数值计算，研究了大水矿井煤层开采过程中底板突水的孕育、发展和发生机制，并进一步探究了水压、关键层厚度、隔水层厚度、强度关键层和隔水层的厚度组合情况、注浆效果对底板突水的影响规律；在典型突水矿井建立了微震监测系统，对注浆堵水帷幕的稳定性进行了微震监测，通过微震监测结果，确定了煤层底板破坏深度，识别出了底板导水通道及其形成过程，判定了底板微震事件异常区，并分析了底板滞后突水影响距离；依据现场微震监测数据，利用数理统计方法，建立了煤层底板突水危险性评价指标与预警模型，并检验了预警模型的可靠性，确定了预警模型的临界值；基于预警模型，建立了基于微震监测的煤层底板突水预警方法，并最终建立了基于微震监测系统、数值计算分析系统、虚拟现实系统、网络传输系统和预警预报分析中心的煤层底板突水预警平台。研究成果为矿井突水灾害的监测、预警和防治工作提供了有力的理论和技术支持。