瓦斯的高效抽采是煤矿灾害治理和清洁能源利用的根本性措施之一。但是，我国大量抽采老孔的存在造成工程与资源的双重浪费，其修复与二次利用技术研究亟待展开，然而作为其理论基础的外力扰动作用下抽采老孔修复增透机理至今少人问津。.本项目旨在基于现有瓦斯抽采钻孔有效寿命统计分析，准确界定抽采老孔概念或划分标准；基于煤岩物理力学参数测试，引入有限元强度折减法，探讨煤层钻孔破坏状态下孔周塑性区分布规律，获取煤层钻孔的整体稳定安全系数、局部稳定安全系数及潜在破裂面，对钻孔稳定性进行定量描述和评价；基于岩石力学、渗流力学及热力学理论，构建含瓦斯煤热-流-固耦合模型并解算，探讨孔周拱体范围的变化规律，厘清拱体形成与破坏的条件，阐释热-流-固耦合作用下抽采钻孔成拱特性；构建模拟试验系统及方法，探讨抽采老孔修复过程中孔周煤体应力及渗透率动态演化机制，揭示外力扰动作用下抽采老孔修复增透机理，论证抽采老孔二次利用潜力。

Efficient gas drainage is one of the fundamental measures for disaster control in coal mine and clean energy utilization. So far, there are a large number of drainage boreholes which have low efficiency in underground coal mines in China. In order to reduce the double waste of engineering and resources, the restoration and reuse technology of those boreholes needs to be carried out urgently. However, there are hardly any reports about restoration and permeability enhancement mechanism of the ineffective drainage borehole under the disturbance action of external force, which is the theoretical basis of the restoration and reuse technology..This project will accurately define the concept or division criterion of the ineffective drainage borehole based on the statistical analysis of the active life of the existing drainage borehole. Based on the measurement of physical and mechanical parameters of coal and rock, strength reduction finite element method will be introduced and the distribution law of plastic zone around the borehole under the failure conditions in coal seam will be discussed, the overall stability safety factor, local stability safety factor and potential slip surface of coalbed borehole will be obtained, and the stability of coalbed borehole will be quantitatively described and evaluated. Secondly, based on rock mechanics, percolation mechanics and thermodynamics, the thermo-fluid-solid coupling model of coal containing gas will be built and solved, the variation law of arch boundary will be discussed, the formation and failure conditions of arch will be clarified, and then the arch-forming characteristics of drainage borehole under the coupling action of thermo-fluid-solid will be explained. Furthermore, simulation test system and method will be constructed, the dynamic evolution mechanism of stress and permeability of coal body around drainage borehole during borehole restoration will be discussed, restoration and permeability enhancement mechanism of the ineffective drainage borehole under the disturbance action of external force will be revealed, and its potential of secondary utilization will be expounded and proved.