瓦斯/应力诱导煤岩损伤-破坏-突出力学演化与致灾机理

Coal and gas outburst is the process of coal damage, destruction to catastrophe. At present, the research of outburst mechanism mainly concentrates on the analysis of the prominent influence factors or the change of physical quantity during outburst, research on mechanical evolution until disaster of coal and gas outburst is less. This project will carry out from the whole process of coal damage, destruction and disaster, and analyse mechanics evolution and disaster induced mechanism of outburst. First, based on the meso-experiment and numerical simulation of coal damage, reveal the initial damage mechanism of gas to coal; Secondly, using the degradation function of mechanical parameters to describe the deterioration effect of initial damage of coal. Existing damage constitutive model of damaged coal will be improved, which will be embedded in the COMSOL numerical software and verified by experiment. The effect of stress and gas on coal damage and damage will be found; Finally, the numerical simulation of the evolution process of coal and gas outburst is carried out. At the same time, with the help of the simulation test of coal and gas outburst, the whole process of disaster before and after the occurrence of disasters will be analyzed, the mechanical evolution and disaster induced mechanism of coal and gas outburst will be revealed. This project is significant to the prevention and control of outburst disaster.

煤与瓦斯突出是煤岩损伤、破坏至灾变的过程，目前对煤与瓦斯突出机理的研究主要集中在分析突出的影响因素或监测突出过程中物理量变化，对煤与瓦斯突出力学演化引发灾害发生的研究较少。本项目将从煤岩损伤、破坏直至灾害发生的全过程开展研究，深入分析煤与瓦斯突出的力学演化和致灾机理。首先，基于瓦斯诱导煤岩损伤细观试验和数值模拟，揭示瓦斯对煤岩的初始损伤作用；其次，采用力学参数退化函数描述煤岩初始损伤下的劣化效应，对煤岩破坏本构方程进行改进，嵌入COMSOL数值软件并与试验验证，揭示应力、瓦斯在煤岩损伤破坏中的作用；最后，对煤与瓦斯突出力学演化过程开展数值模拟，同时借助煤与瓦斯突出模拟试验，实现灾害反生前、发生后的全过程分析，揭示煤与瓦斯突出力学演化与致灾机理。本项目对煤矿瓦斯灾害防治具有重要意义。

煤与瓦斯突出是气固耦合作用下煤岩损伤破坏直至灾变的动力学过程，严重制约我国煤炭安全高效开采。针对煤与瓦斯突出机理不清和灾变演化前兆信息缺乏难题，本项目自主研发了煤岩瓦斯气固耦合相似材料和气固耦合模拟试验仪器，开展了煤岩吸附瓦斯损伤力学试验、应力/瓦斯耦合作用下煤岩破裂试验，并基于试验成果开发了相应的数值模拟算法。监测了煤岩损伤破坏过程声发射、应变场、红外辐射温度场等信息的响应规律，分析了煤岩损破裂过程多参量指标的前兆性和显著性。进行了大尺度真三维煤与瓦斯突出相似模拟试验，在实验室还原了煤与瓦斯突出演化灾变过程，获得了煤与瓦斯突出全过程和灾变时刻的声发射、应力、瓦斯压力响应规律。主要成果如下：. 1) 基于含瓦斯煤气固耦合特性，研制了具有良好的代表性和通用性的煤岩瓦斯气固耦合相似材料，实现了对煤岩、瓦斯的高度真实和安全模拟。改进研发了一套“可视化恒定容积气固耦合试验装置”，实现了对试样变形破裂过程的实时可视化监测。揭示了CH4、He、CO2及其多元气体在煤中的吸附特性和气体吸附诱发煤样损伤及强度劣化机理。. 2) 基于煤岩体细观结构特征，在大型通用数值分析软件平台上，开发了考虑煤岩体细观结构和非均质性的数值模拟方法。提出了煤岩损伤破断本构模型和实现方法，揭示了煤岩“沿晶断裂”和“沿晶、穿晶混合断裂”的典型破坏模式。揭示了非均质煤岩体试件破坏过程声发射、应变场、红外辐射温度场等信息的响应规律，提出了基于数据融合及智能识别的损伤破坏前兆判识方法。. 3) 进行了大尺度真三维煤与瓦斯突出相似模拟试验，在实验室还原了煤与瓦斯突出演化灾变过程，获得了煤与瓦斯突出全过程和灾变时刻的声发射、应力、瓦斯压力响应规律，并提出了煤与瓦斯突出力学演化规律和能量机制。.本项目对于揭示煤与瓦斯突出机理和灾害防控治理具有重要理论意义。