基于爆炸应力波和构造煤带孕育煤与瓦斯突出危险状态的模型

A model based on explosive stress wave and tectonic coal zone which gestate dangerous state of coal and gas outburst

针对华南地区突出矿区分布广泛、煤与瓦斯突出事故严重的现状,结合该地区地质构造复杂构造煤广泛分布和大部分矿井采用炮采炮掘工艺的特点,提出一种基于爆炸应力波和构造煤带孕育煤与瓦斯突出危险状态的模型,并对该模型进行了理论分析。研究表明:爆炸应力波在传播过程中形成的稀疏波会引起该波经过的区域密度减小、体积增大,煤层瓦斯压力降低,进而破坏煤体瓦斯原有吸附平衡状态,大量吸附瓦斯解吸导致煤层瓦斯压力上升;当掘进工作面前方煤体一定深度存在构造煤带时,爆炸应力波从掘进工作面爆源传至未破坏煤体与构造煤带交界面,由于爆炸应力波的反射加强作用使构造煤迎波一侧未破坏煤体产生拉伸破坏,而掘进工作面前方存在的应力集中带不会引起爆炸应力波对煤体产生反射拉伸加强破坏作用;掘进工作面向构造煤带推进需要周期性的爆破作业,爆炸应力波的强度随着距爆源的距离增加而衰减,产生的爆炸应力波对煤体的瓦斯解吸作用和破坏作用不断增强,产生爆炸应力波的累加效应。

In terms of the current state of widespread and serious coal and gas outburst problem in south China,by combining widespread tectonic coal,complex geological structure and the process of blast mining and driving used in most ofthe mines,a model based on tectonic coal and explosive stress wave which gestate the dangerous state of coal and gas outburst was proposed and was theoretically analyzed. Study shows that the sparse wave formed by explosive stress wave would lead to coal＇s density decrease and volume expansion,coal seam gas pressure decrease,coal seam methane adsorption unbalance,and the desorption methane which converted from adsorption methane finally leads to the rise of coal seam gas pressure. When there are tectonic coal zone inthe front of drivageface,the explosive stress wave from explosion source located in drivageface propagates to the interface between no-destruction coal and tectonic coal zone. Due to the strengthened effect of the reflection wave,no-destruction coal which located between tectonic coaland drivageface generates tensile failure. When there are stress concentrated zones inthe front of the drivageface,coal mass would not generate tensile failure like above. With the periodic blasting and driving towardthe tectonic coal zone,the destruction and methane desorption effects on coal mass is constantly strengthened. The strength of explosive stress wave constantly decreases with the increase of distance from explosion source. Finally,the process generates a blastingaccumulation effect.