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以掘进巷道前方分布的弹、塑性组合煤体为研究对象,基于应力波的传播规律,研究冲击载荷作用下煤体中应力波的传播过程,加、卸载波相互作用下拉应力波的形成及作用机理。研究表明:弹、塑性组合煤体在冲击载荷作用前后,加、卸载波在波阻抗不同的分界面将发生反射与透射,形成多束卸载波;卸载波的作用能产生拉应力,易致使煤体发生破坏;冲击载荷作用下掘进工作面前方塑性煤体与弹性煤体的分界面附近煤体中易形成拉应力较大的区域,导致煤体发生急剧损伤、瓦斯解吸速度急剧增加、瓦斯压力急剧上升,从而导致煤与瓦斯突出事故的发生,是由内至外的发展过程;加、卸载应力波在孔洞周围的弹、塑性煤体传播过程中会发生多次反射与透射产生多束卸载波,卸载波之间相互作用产生的拉应力,可使煤与瓦斯突出过程中呈现层裂现象。
Based on the propagation law of stress wave, the propagation process of stress wave in coal mass under impact load and the formation and action of tensile stress wave under the interaction of loading and unloading waves are studied in this paper. mechanism. The results show that the loading and unloading waves reflect and transmit at the interface with different wave impedances before and after the impact load. The unloading wave can generate tensile stress and easily cause the coal Body under the action of impact load in front of the excavation face of the plastic coal and elastic coal near the interface easy to form a large tensile stress in the region, resulting in a sharp damage to coal, gas desorption rate increased dramatically, gas pressure The rapid rise of coal and gas outburst causes the development process from the inside to the outside. Adding and unloading the bombs around the holes caused by the stress wave, multiple reflections and transmissons occur during the propagation of the plastic coal. Waves, unloading waves generated by the interaction between the tensile stress, coal and gas outburst can show the phenomenon of splitting.