高温热流诱导煤体孔裂隙结构响应及损伤增透机制研究

煤层瓦斯严重威胁着煤矿安全生产的同时也是一种清洁高效能源，随着开采向深部延深，高应力低渗环境成为制约原始煤层瓦斯安全高效开采的关键因素。注热开采被视作可能成为未来开发深部煤层瓦斯的热门技术，而目前高温热流增透相关的试验与理论研究还存在不足。项目以高温热流诱导煤层渗透率变化为主线，以不同变质程度煤为研究对象，通过研发外加三轴应力的高温热流煤样处理装置获得不同原岩应力条件和热效应作用的实验样品，采用多维度表征、宏微观定量分析和多样化试验的创新研究方法，系统研究热效应对煤体孔裂隙结构改造作用机制和附加热应力对含瓦煤基质的微观变形损伤作用特征，探索高温热流效应诱发受载煤体动态损伤演化与渗流耦合机制，在此基础上，建立高温热流效应诱发受载含瓦斯煤体热-流-固耦合模型，获得抽采作用下注热煤层多物理场耦合作用特征，最终揭示外加热流条件含瓦斯煤增透机制。上述研究为深部煤与瓦斯资源安全高效开发提供理论指导。

Although coal seam gas is a factor threatening mining safety, it is also a kind of clean and high-efficient energy. With the deepening of coal mining, the environment of high in-situ stress and low permeability becomes the key factor restricting the safe and high efficient exploitation of gas in the virgin coal seam. Heat flow injection mining has been widely recognized by the scholars as a potential popular mining technique for deep coal seam gas in the future. However, there are still some deficiencies in the experimental and theoretical researches on coal permeability enhancing mechanism induced by high temperature heat flow at present. In this project, taking the coal seam permeability variation induced by high temperature heat flow as the main line, coal samples of different metamorphic degree are selected to be the research objects, and the experimental samples under different in-situ stress conditions and thermal effect were obtained by using the newly developed equipment which could process the coal samples under the high temperature heat flow with additional triaxial stress. Using the innovative research methods of multidimensional characterization, macro-micro quantitative analysis and diversified test, we carry out a systematic study on the transformation of the pore-fracture structures by the thermal effect and its additional thermal stress influence on micro-deformation and damage characteristics of the gassy coal matrix; thus, the coupling mechanism between the dynamic damage evolution and gas seepage of gassy coal are explored under the high temperature heat flow. Based on the aforementioned researches, the heat-flow-solid coupling model of the in-situ coal mass under the high temperature heat flow effect could be established and the multi-physical field coupling characteristics could be obtained during the gas drainage period. Finally the permeability enhancing mechanism by the high temperature heat flow could be revealed. The above researches could provide theoretical guidance for safety and high-efficient exploitation of deep coal and gas reservoirs.