突出煤体的粉化破坏机理研究

The coal damage mechanism and gas interaction are main scientific issues for research coal and gas outburst. Based on the knowledge of the pre-outburst coal that has undergone the complex stress path, and gas desorption promoting coal damage, intensively combined the practice of coal excavation, based on the development of equipment and related experiments, mathematical and mechanical theoretical analysis, numerical simulation and similar material experiment research on the pulverization mechanism of outburst coal. The main research contents include: 1) Based on different mining conditions and the dynamic evolution path of the coal stress in disturbe area, experimental studies are carried out under the circumstance of coal static stress effect with gas, the coal damage process is analyzed, prominent damage state is obtained; 2) The experiments for deformation of coal and gas desorption, as well as its role in promoting the coal destruction process, and the extent of residual deformation of scale coal destruction is analyzed; 3) The experiemental system for realization of high-pressure gas system stress testing transient unloading coal deformation damage is developed, different stress transient unloading coal for varying degrees of damage is carried out, the experiments of different gas pressure transient unloading and transient stress as well as gas pressure while unloading are conducted. The results of this research have significant meanings in understanding the mechanism and process of coal and gas outburst, also lay theoretical and technical basis for effective control for gas disaster, and to development appropriate strategies for gas disaster prevention .

煤体的破坏机理及其与瓦斯的相互作用是研究煤与瓦斯动力灾害的主要科学问题。本项目基于突出前煤体已经历复杂的应力路径、瓦斯解吸促进煤体破坏的认识，紧密结合工程实际，以设备研发及相关实验为基础，以数学力学理论分析、数值仿真、相似材料模拟等手段，开展突出煤体粉化破坏机理研究。研究内容有：1)基于不同开采条件下扰动区煤体应力动态演化路径，开展含瓦斯煤体静态应力作用下实验研究，分析煤体破坏过程，得出煤体突出前的损伤状态；2)煤体解吸瓦斯变形实验及其在煤体破坏过程中的促进作用，分析残余变形对煤体破坏程度的标度；3)研制实现高压瓦斯及应力瞬态卸载煤体变形破坏实验系统，开展不同破坏程度煤体不同应力瞬态卸载、不同瓦斯压力瞬态卸载及应力和瓦斯压力同时瞬态卸载实验。研究成果对深入了解煤与瓦斯突出机理及突出发展过程具有重要作用，并为有效控制瓦斯灾害和开发相应的防治技术奠定理论和技术基础。

本项目基于突出前煤体已经历复杂的应力路径、瓦斯解吸促进煤体破坏的认识，以数学力学理论分析、数值仿真、相似材料模拟等手段，开展突出煤体粉化破坏机理研究。主要进行了以下工作：（1）采用数值模拟、相似模拟方法研究了采区围岩应力分布及其动态演化特征，以及多煤层开采过程中上覆岩层的移动规律、破坏规律、垮落形态、地表下沉机制；（2）建立了煤体破坏过程的应变软化模型，得出了钻孔围岩破坏区、塑性区和弹性区范围，计算了复合应力作用下裂纹尖端应力强度因子；（3）通过图像处理技术提取煤体破坏过程裂纹特征参数，并建立煤体的脆性破坏本构模型；（4）利用场发射环境扫描电镜，研究了水在煤体中的赋存状态及其动态变化过程，建立了水分对煤体孔隙率、渗透率影响的数学模型；（5）基于工作面前方应力变化及煤体破坏过程，建立了煤体-瓦斯固流耦合模型，研究了瓦斯在煤体中的流动规律；（6）研究了巷道破坏区范围及其矸石堆支护特性，软弱顶板破坏特征及其支护技术。