流固耦合作用下煤岩体定向水力压裂导控增透机理研究

Coal and gas outburst was an extremely complex dynamic phenomena and severely restricted safety production of coal mine. Hydraulic fracturing was one of the effective ways to prevent coal and gas outburst and other dynamic disasters. Based on the hydraulic fracturing theory and the maximum circumferential tensile stress criterion, the mechanical model of crack initiation and propagation in coal and rock mass under a given stress state is established considering the joint action of gas pressure and water pressure. Revealing the mechanical mechanism of crack initiation and propagation under the action of water-gas co-propagation. The coal-rock hydraulic fracturing test system, acoustic emission positioning system, tracer tracing method and micro-nano rock three-dimensional micro structure scanning system are used to conduct directional hydraulic fracturing test of annular wedge groove and axial wedge groove under given gas pressure and stress. Study on the microfissure development characteristics and extended evolution law and guiding mechanism of macroscopic cracks under different directional hydraulic fracturing modes. Exploring the influence mechanism of fluid-solid coupling on directional hydraulic fracturing control of coal and rock mass. Constructing a three-dimensional fracture network model combining macroscopic and microscopic fractures in coal rock. Revealing the influence law and anti-reflection mechanism of primary and secondary cracks and micro-fracture parameters on directional hydraulic fracturing. The research results of the project can lay the theoretical and technical basis for effective prevention and control of coal and gas outburst and other dynamic disasters by using the guidance and control method of directional hydraulic fracturing.

煤与瓦斯突出是一种极其复杂的动力现象，严重制约了煤矿的安全生产，水力压裂是防治煤与瓦斯突出等动力灾害的有效途径之一。项目基于水力压裂理论和最大周向拉应力准则，构建给定应力状态下考虑瓦斯压力、水压共同作用的煤岩体裂纹起裂扩展力学模型，揭示水气共驱作用下裂纹起裂与扩展的力学机理；采用煤岩体水力压裂试验系统、声发射定位系统、示踪剂追踪方法和微纳米岩石三维细观结构扫描系统开展给定瓦斯压力和应力条件下环形楔形槽与轴向楔形槽导控定向水力压裂试验，研究不同定向水力压裂方式下微裂隙发育特点和宏观裂缝的扩展演化规律与导控机制，探索流固耦合作用对煤岩体定向水力压裂导控的影响机制，构建煤岩体内宏观裂缝与微观裂隙相结合的三维裂缝网络模型，揭示主次裂缝与微裂隙参数对定向水力压裂效果的影响规律与增透机理。项目研究成果可为采用定向水力压裂导控的方法实现煤与瓦斯突出等动力灾害的有效防控奠定理论和技术基础。

煤与瓦斯突出是一种极其复杂的动力现象，严重制约了煤矿的安全生产，水力压裂是防治煤与瓦斯突出等动力灾害的有效途径之一。本课题建立了考虑水压等因素作用下煤岩体裂纹起裂扩展力学模型，分析了水力压裂的影响因素，分析了裂纹尖端应力增加机制，获得了水力压裂裂纹起裂与扩展的规律；搭建了流固耦合作用下煤岩体定向水力压裂模型，开展了煤岩体定向导控水力压裂试验，分析了裂缝起裂位置特征，分析了裂缝起裂与扩展过程中水力主裂缝长度与方向变化的规律，研究了流固耦合作用下煤岩体定向水力压裂过程中裂缝起裂扩展的规律；研究了不同条件下导控水力压裂过程中裂缝的起裂位置、扩展方位、水力裂缝的展布形态，分析了定向水力压裂过程中微裂缝发育特点和宏观裂缝的扩展演化规律，获得了定向水力压裂的压裂效果与增透机理。.在项目研究期间发表学术论文8篇，其中SCI检索6篇，EI检索2篇；申请发明专利3项，授权2项。获安徽省2020年度高校优秀青年骨干人才国外访学研修项目、安徽省2022年度高校优秀青年人才支持重点项目资助，获得安徽省教学成果二等奖。项目研究期间培养硕士研究生3名，其中1名已取得硕士学位，在读硕士研究生2名，协助培养1名博士研究生，已获得博士学位。项目直接经费25万元，研究期间支出经费17.23万元，各项支出基本与预算相符，剩余经费7.77万元，剩余经费计划用于本项目后续研究的支出。