积水采空区围岩导水通道形成机理及突水、疏放渗流规律研究

In this project, the first work is to build the typical hydrogeological structure model with the status of goaf water and cases of water inrush. And the dynamic evolution process of long-term water immersion and water inrush channel will be analyzed based on field detection, testing and experiment. Then, the elastic velocity field and damage field of the surrounding rock and coal pillar will be inversed based on the theory of geophysical source mechanism. The coupling mechanics model of damage and seepage flow will be established to depict formation of the water-conductive channel and the flow transition process, from non-Darcy high-velocity flow to the NS pipe flow, between different goafs in the dynamic evolution process of surrounding rock mass. Based on the proposed model, the distribution characteristics of the superimposed stress field, the evolution law of the three zones and the high velocity seepage mechanism under complex flow regime during the formation of water-conductive channel will be revealed. And then, a theory and method for predicting water inflow of waterlogged goaf, flowing from non-Darcy flow to N-S flow, will be proposed. Finally, an optimizing model for project layout of the water discharge within the goaf will be established based on the accurate detection of the goaf water boundary, in situ test, monitoring information analysis and numerical simulation on rock damage and seepage field evolution. Furthermore, a method for calculating the size of waterproof coal pillar considering long-term immersion mechanism can be proposed. The project will provide scientific theories and analysis methods for the prediction and controlling methods of goaf water damage in Shanxi province, even in China.

本项目首先分析山西省老空水现状、突水案例，建立典型水文地质结构模式，通过现场探测、测试及实验分析采空区煤柱长期浸水弱化突水通道动态演化过程。其次，基于地球物理震源机制理论反演采空区围岩及煤柱弹性波速场及损伤场，建立采动岩体损伤-渗流耦合力学模型，描述围岩动态损伤演化过程、导水通道形成与采空区之间非Darcy高速流到N-S管流流态转捩过程，揭示采空区围岩叠加应力场分布特征、三带演化规律及导水通道形成的复杂流态条件下高速渗流机理，提出预测老空水非Darcy流到N-S流突水水量的理论和方法。最后，通过老空水边界的精准探测、岩体损伤场渗流场演化的数值模拟和现场探测、监测信息分析，建立采空区积水疏放工程布置优化模型，提出考虑防水煤柱长期浸水弱化机理及留设尺寸计算方法。项目实施为山西省乃至我国大量采空区积水水害孕育机理及预测防治提供科学理论和分析手段。

本项目以山西省煤矿采空区突水问题为研究背景，围绕“复杂应力作用下采场围岩重复扰动、长期浸水损伤力学机理”和“积水采空区突水非线性Navier-Stokes管流行为”两个关键科学问题展开系统性研究，已取得以下研究进展：1）系统收集山西省煤矿水文地质勘探与突水事故资料，对45次老空突水案例调研整理，将老空水害划分为4大类和12个亚类，提出和阐明了各类老空水害的水文地质结构模式与突水机理，构建了山西省典型老空区水害3D GIS信息化云平台；2）以西山煤电西曲矿18401采面及其覆岩为研究对象，借助孔内电视、微震监测、地表裂缝观测等实测方法，研究了该矿2+3号、8号煤下行重复采动前后的覆岩“三带”发育特征；3）结合西曲矿实测结果，运用数值模拟、理论分析方法，研究了重复采动层间主关键层的破断规律与覆岩“三带”的演化规律，并提出了基于微震监测数据反演分析以判别岩层渗透特性、导水通道形成、岩层损伤破断的理论方法；4）研发浸水弱化实验设备，开展了浸水砂岩强度试验，统计了山西省典型煤样的易浸水弱化程度，并建立了扩散、渗流、应力多场耦合的损伤力学模型，开发了数值计算方法，揭示煤柱破坏及导水通道形成机理，阐明了煤柱弱化规律及裂隙渗流特征；5）研制了可进行高速渗流实验的“平面水力输沙试验装置”，结合实际开展了不同裂隙网络开度及角度、不同颗粒级配、不同水力梯度等条件下的渗流试验，进而建立了导水裂隙带混合流体非达西渗流模型，并以姜家湾煤矿突水事故为工程实例进行数值模拟分析，得到了老空突水过程中压力、速度、孔隙率及浓度等时空演化规律。研究成果发表学术论文38篇，其中SCI收录29篇，EI收录9篇。申请和授权发明专利19项，软件版权登记7项，主编《矿山采动岩体非线性渗流试验、模型与工程应用》1本。培养博士毕业7人，硕士6人，获得省部级奖励2项。项目研究可为山西省采空区积水水害孕育机理及预测防治提供科学理论和分析手段。