深矿井高承压水底板异常破坏致灾机理及其应用

Water-inrush from Coalbed floor is an important type of water hazards in coal mines. For the recent decades, researches and practices focused on the mechanism and prevention of floor water-inrush have been carried out and abundant achievements have been made. With the increase of coal mining depth, the threat of floor confined water is more and more serious. Previous researches mostly focused on the mining in the shallow coal mines. The understanding to the special damage rule in the floor of deep mine is inadequate. This project will pay great attention to the relationship between the movement of overlying strata and the damage of bed floor under the condition of deep mine through field measurement, theoretical analysis, indoor experiments, and similar material simulation and computer simulation, etc.. The mechanism of abnormal floor damage, with development rule of the abnormal damage will be lucubrated by monitoring the stress distribution, the dynamic characteristics of damage in the coalbed floor, and the site measure to the damage depth, combined with the pressure change rule of overlying strata. The formation mechanism of the water inrush channel will be explored through the analysis to the high pressure water seepage in fractured damage rock. The location prediction of water inrush will be carried out by considering the abnormal damage zone, the head pressure of floor confined water and the water abundance in aquifer. The research results of the project will give a supplement to the understanding of floor damage rule, and guide prevention and control of water disasters in the deep mining.

煤矿底板突水是重要的煤矿水害类型。数十年来，人们对底板突水机理和水害防治技术进行了大量的研究和实践，取得了丰富的成果。随着煤矿开采深度的加大，底板承压水威胁也越来越大。以往研究多集中在中浅部开采的矿井，对深矿井底板特殊破坏规律认识不足。本项目拟通过现场实测、理论分析、室内实验、相似材料模拟和计算机模拟等，研究深矿井开采条件下采场覆岩运动与底板破坏之间的关系，探索煤层底板异常破坏的机理；通过监测底板应力分布、底板动态破坏状态特征、现场实测工作面底板破坏深度，结合覆压变化规律，寻求底板异常破坏的发生机理、异常破坏带发育规律；通过对高承压水渗流对裂隙岩体损伤断裂分析，探究突水通道的形成机制；结合含水层的富水性、水头压力等因素，对底板突水危险性进行空间定位预测。本项目研究成果将补充以往对底板破坏发育特征和规律的认识，对丰富底板突水理论，对指导深矿井底板水防治具有重要的理论和现实意义。

随着煤矿开采水平的延伸，越来越多的矿井进入深部开采，煤层开采受到底板承压水的威胁越来越严重。深矿井煤层底板突水机理及预测成为亟待解决的关键科学问题。本项目以鲁西煤田部分大采深矿井为例，将煤层开采上覆岩层运动、覆岩压力、采场底板应力分布、煤层底板岩体破坏以及底板突水定位预测等内容系统地联系起来进行综合研究。提出采场覆岩压力拱边界力学判据，系统研究了工作面宽度、工作面推进距离、埋深、开采煤层厚度及侧压系数对压力拱形态的影响机制，揭示了煤层开采过程中覆岩压力拱拱体动态演化过程。探讨了压力拱与裂断拱之间的关系，揭示了两者的同步性发展过程。采用理论分析、数值模拟与现场监测相结合的手段研究了典型工作面底板采动应力分布特征及底板异常破坏规律，获得煤层底板破坏是随工作面开采而呈波浪式发展、具有一定的阶段性和周期性的科学认识；构建了底板破坏带发育的分阶段模式，提出了覆岩最大裂隙拱、应力拱和底板异常破坏带的初始步距约为工作面宽度，周期步距近似为工作面宽度一半的观点。将煤层底板岩体异常破坏带与煤层底板突水定位预测联系在一起，指出了当工作面掘进至底板异常破坏带发育的初始步距或周期步距时是底板突水危险地段，并通过新汶煤田良庄煤矿51302工作面的井下电阻率动态监测结果和突水实例验证了本项目研究结论。研究成果是对以往浅部开采时底板突水研究成果的补充，丰富、发展了矿井底板突水理论，对预测大采深矿井底板突水，预防水害发生具有重要的理论和现实意义。