气固耦合作用下复合灾害多尺度能量竞争演化机制研究

The mechanism of energy evolution under gas-coal coupling is not clear. It is difficult to control the compound disaster in deep coal rock. The multi-scale energy competition hypothesis is presented that the process of compound disaster is the process of multi-scale competition evolution of gas internal energy and coal-rock deformation impact energy micro-accumulation, macroscopic manifestation and energy release on engineering scale caused by exploiting. Technique of nuclear magnetic reasonance will be introduced and experimental inversion method will be used. Based on the experiments of extraction impact and pressure relief with engineering scale parameters, the characteristics of macro-parameter variation of compound disaster with different load combinations will be explored. Compound disaster microinjection simulation instrument with high confining pressure, high axial pressure and high pore pressure will be developed. The nuclear magnetic experiment with same parameters will be performed. Law of microscopic nuclear magnetic indexs such as gas adsorption capacity, free capacity and pore radius will be obtained. Corresponding with parameters obtained by macroscopic experiment such as impact energy index,gas interal energy, critical gas pressure and impact strength,law of engineering scale will be inversed. The evolution mechanism of multi-scale energy competition will be revealed. Using the correspondence with T2 spectrum of lateral relaxation time and parameters of macroscopic seepage rate and microscopic pore deformation, macro-micro energy competition evolution will be linked with potential energy change of coal microstructural deformation and potential energy qualitative change of gas pressure. The mechanics model of compound disaster will be established. Finally the occurance criterion of compound disaster will be presented. The scientific reference for the forecast and prevention of compound disasters will be proposed.

瓦斯-煤耦合作用下能量演化机理不清是复合灾害难以防治根本原因。提出多尺度能量竞争假说，认为复合灾害是人为采动致瓦斯内能和煤岩变形冲击能由微观累积、宏观显现、工程尺度能量释放的多尺度竞争演化致灾过程。引入核磁共振技术，采用实验反演方法，基于工程尺度参数的抽采冲击和卸压突出实验，探究不同荷载组合复合灾害宏观参数变化特征，研制高围压、高轴压、高孔隙压复合灾害微观孕育模拟仪，进行相同参数核磁实验，得到瓦斯吸附量、游离量、孔道半径等核磁微观指标变化规律，与宏观实验冲击能指数、瓦斯内能、临界瓦斯压力、冲击突出强度等参数对应，反演工程尺度致灾规律，阐明多尺度能量竞争演化机制。利用核磁横向弛豫时间T2与微观孔径对应关系、煤微结构变形势能量变到瓦斯压力势能质变将宏微观能量竞争演化联系起来，建立复合灾害力学模型，并辅以数值求解，提出复合灾害能量判据，为完善现有复合灾害预测和防治提供科学参考。

目前深部煤岩灾害类型由单一型向复合型转化，瓦斯-煤耦合作用下能量演化机理不清是复合灾害难以防治根本原因。提出多尺度能量竞争假说，认为深部煤岩复合灾害孕育、潜伏、发生、发展实质上是人为采动致瓦斯-煤气固耦合作用下，瓦斯内能和煤岩变形冲击能由微观累积、宏观显现、工程尺度能量释放的多尺度竞争演化过程。以典型突出主导型复合灾害矿井为研究对象，根据现场工程尺度下复合灾害发生条件，经相似理论计算确定了实验室尺度下复合灾害发生的实验参数（即复合灾害孕育、启动、发生发展过程中围压、轴压和孔隙压的加卸载条件），研制了复合灾害宏观模拟实验系统，进行了不同荷载组合下复合灾害发生全过程宏观模拟实验，获得复合灾害宏观参数如临界瓦斯压力、冲击突出强度、煤体温度、冲击力等变化特征，结合声发射测试系统，分析了复合灾害发生发展能量演化过程，给出了基于声发射能量特征的复合灾害危险性指标。利用研制的变轴压、变围压、变孔隙压非磁性三轴复合灾害孕育模拟仪，引入核磁共振谱技术，实验反演了复合灾害发生微观过程，获得了以核磁信号强度为微观定量指标的瓦斯吸附量、游离量、孔道半径变形量、横向弛豫时间T2等变化规律，与宏观实验得到的有效应力、临界瓦斯压力、冲击突出强度、煤体温度等参数对应起来，反演工程尺度下复合灾害发生规律。从能量竞争演化角度，建立了瓦斯内能和煤体变形能竞争演化的复合灾害力学模型，给出了复合灾害能量判据，阐明瓦斯-煤耦合作用下复合灾害能量竞争演化机制，为复合灾害监测预警开辟新的研究方法和途径，为完善现有复合灾害预测和防治提供了科学参考。