向斜构造煤与瓦斯突出机理探讨

为了确定向斜构造煤与瓦斯突出机理，从应力、煤体结构特征和瓦斯压力及含量等方面对向斜构造进行了分析.利用弹性梁的应力、应变理论，分析了煤层与围岩组成的软硬互层系统的层间滑动特征和应力-应变特征、煤体宏观与微观结构特征、瓦斯压力与瓦斯含量分布特征.研究表明，向斜构造的两翼与轴部中性层以上为高压区，中性层以下为相对低压区，距离向斜轴部越近，主应力及其梯度越大.向斜构造形成过程中的层间滑动造成煤体原生结构遭到破坏，煤体强度降低，煤层增厚.向斜构造部位瓦斯生成量亦相对较高，同时中性层以上煤(岩)体中的裂隙和孔隙被压密、压实而闭合，阻止了下部瓦斯的向上逸散，中性层以下的张性作用下的断裂或折裂面、煤体中的割理、节理等降低了解吸压力，形成良好的瓦斯聚集空间，也有助于煤层中吸附瓦斯的解吸，使得向斜轴部瓦斯含量较高.向斜构造同时具备的高地应力、高瓦斯压力(含量)和构造煤发育等3个因素是其发生煤与瓦斯突出的主要原因.

Discussion of coal and gas outburst mechanism of syncline

In order to determine the mechanism of the coal and gas outburst in the syncline,it should be analyzed from stress,the property of coal structure to the press and content of gas in the syncline.With the stress and strain theory of elastic beam,the follow was researched in alternative distributed soft and hard system constructed by the coal and rock: the interlayer glide the characteristic,the stress-strain characteristic,the macro and micro structure characteristic of the coal and the gas press(content) characteristic.The research shows that it is high stress region at both schank and axis above neutral layer,low pressure field below the neutral layer.The shorter the distance is to synclinal axis,the larger the stress and the grads.During the syncline structure was formed,the primary structure of the coal was destroyed because of interlayer glide,and this generated the tectonic coal.The fracture and pore structure above the neutral layer was compressed to close,so the gas was prevent to emission.The space under neutral layer formed a good condition for gas storage.So the gas content was higher in axis than schank.So the main reason of coal and gas outburst in syncline is at where high stress,high gas content(press) and tectonic coal are formed at the same time.