煤层底板隐伏溶洞突水灾变演化机制及其前兆信息研究

Water inrush from concealed confined karst cave in Permian Maokou Formation is a great threat to the exploitation of the Longtan Formation coal seams in South China. However, current research on mine water inrush mainly focus on the water inrush from Ordovician thick limestone in North China, water inrush from karst collapse column, and water inrush from fault, etc. the research on the mine disaster of water inrush from concealed confined karst cave in Permian Maokou Formation is little and not deep. This project first plans to systematically summarize the geological structure characteristics of water inrush from coal floor concealed karst cave and the key factors that cause water inrush by field investigation and case study. Moreover, the three-dimensional flow-solid coupling physical simulation test and numerical simulation method are used to reconstruct the dynamic process of water inrush, and capture the information of stresses, displacements, seepage pressures and acoustic emission in the aquifuge to analyze the variation of each physical field and multi-physical field coupling effect, the catastrophic evolution mechanism of the water inrush from coal floor concealed karst cave is revealed from the perspective of multi-field information evolution of the surrounding rock. Besides, according to the collected data, the difference of the multiple information response between the normal mining area and the water inrush area is compared to study the relationship between multiple information mutation and water inrush formation, at last reveal the precursory information characteristics of the water inrush from coal floor concealed karst cave. The study will be helpful for the further understanding of karst cave water inrush mechanism, and provide scientific basis for the monitoring and early warning of water inrush.

茅口组灰岩隐伏承压溶洞突水对南方龙潭组煤层的安全开采带来了极大的威胁，但目前的矿井突水研究主要集中在华北奥陶系巨厚层灰岩突水、岩溶陷落柱突水和断层突水等领域，对茅口组灰岩溶洞突水的研究较少，且不深入。本项目拟通过现场调研和案例分析，系统总结煤层底板隐伏溶洞突水的地质结构特点及致灾关键因素，通过三维流-固耦合物理模拟试验和数值模拟方法，真实再现溶洞突水的动态过程，全程捕捉突水过程中隔水层内的应力、位移、渗压和声发射变化信息，分析各物理场的变化规律及相互间的耦合效应，从围岩多场信息演变角度揭示煤层底板隐伏溶洞突水的灾变演化机制，同时根据采集到的数据，比较正常开采区和突水发生区的多元信息响应差异，研究多元信息突变与突水形成之间的关系，确定煤层底板隐伏溶洞突水的前兆信息特征，为溶洞突水灾害现象的解释和监测预警提供科学依据。

茅口组隐伏承压溶洞突水对我国南方龙潭组煤层的安全开采带来了极大的威胁，为了有效的揭示煤层底板溶洞突水这一灾害现象，课题组通过现场调研、理论分析、室内试验和数值模拟分析等手段，开展了大量与之相关的研究工作，取得了以下成果：总结了贵州黔北矿区的岩溶发育规律、地下水赋存条件及其对煤矿安全开采的影响特征；将溶洞与煤层之间的隔水岩体简化为由无数积分薄圆板构成的圆锥台体，建立了煤层底板富水承压溶洞突水力学模型。运用突变理论中的尖点突变模型，研究了系统的临界稳定状态，推导了溶洞突水的力学判据；基于区域地质构造、水文地质条件及流固耦合理论，建立了煤层底板隐伏溶洞突水流固耦合模型，分析了煤层底板隐伏溶洞突水过程中围岩内应力、位移、塑性区、孔隙水压力的耦合演化规律及整个突水水流路径下的地下水动力特征，总结了溶洞突水前兆信息特征和地质因素改变对溶洞突水的影响作用；根据黔北矿区煤层底板隔水层的岩性组合特点，从数据的易采集性和代表性出发，选取了隔水层阻水能力评价指标，建立了基于GIS与非线性数学理论的煤层底板隔水层阻水能力多源信息评价方法，可以有效刻画隔水层阻水能力受多因素控制且具有非常复杂形成机理的特征。