煤与瓦斯突出损伤动力演化机理

Damage dynamical evolution mechanism of coal and gas outburst

煤与瓦斯突出中力学性质表现得相当复杂。目前研究很少考虑瓦斯压力梯度对煤的流变破坏作用。本文中基于对煤岩力学性质新的认识,从煤岩损伤破坏的角度出发,综合考虑煤岩的物理力学性质,包括流变性质、地应力和瓦斯压力等因素。根据煤的力学试验结果所表现的非线性弹性性质,在分析瓦斯压力、地应力分别在突出过程中所起的作用基础上,将煤与瓦斯突出具有强烈时间效应的动态力学过程分为准备、发动、发展和终止4个阶段。对瓦斯压力、地应力和重力作用下煤的加速损伤演化所引起的煤与瓦斯突出进行了发生机理的阐述,从而得出煤壁内部瓦斯压力梯度是突出的主要动力源,地应力只是对突出起到辅助作用。对煤岩灾变的延期性、孔洞形状、声发射特征、相对瓦斯涌出量大大超过煤层瓦斯含量、突出煤的分选性、突出的终止过程等现象作新的解释和定性分析。

： Mechanical properties of coal and gas outburst are quite complex. The destruction of gaspressure gradient on the coal flow is rarely considered in present study. Based on the new understanding of coal mechanical properties, considering the damage of coal, this paper comprehensively considers the physical and mechanical properties of coal, including the rheological properties, ground stress and gas pressure etc. According to the nonlinear elastic properties of coal in the mechanical test results, based on the effect of gas pressure and ground stress in the outburst process, the coal and gas outburst is dynamic mechanical process with a strong time effect, which is divided into four stages： preparation, launch, development and termination. The article describes the occurrence mechanism of coal and gas outburst that caused by the accelerate damage evolution in the gas pressure, stress and gravity. Consequently coal gas pressure gradient within the wall is the main power source. The ground stress only plays a supporting role in the outburst. The article also explains and analyzes the extension, hole shape, acoustic emission characteristics, relative gas emission, sorting of outburst coal, termination process of outburst and so on in coal disaster.