【摘要】 为获得不同推进速度下煤岩体的采动力学行为特征,通过轴压和围压分别模拟不同推进速度下垂直应力、水平应力,采用增轴压降围压的方式模拟煤岩体的采动力学行为,同时采用数值模拟和工程实践相结合的方法对不同推进速度下煤岩体的采动力学行为进行研究。结果表明:在围压卸载速率相同的条件下,随着轴压加载速率(推进速度)的增加,煤体的峰值强度、轴向应变和横向应变呈增大趋势,在峰值阶段产生了较大的轴向应变和横向应变,呈现出一定的延性,破坏形式具有塑性特征;在轴向加载和围压卸载的综合作用下,煤体体积一直处于膨胀变形状态,围压的卸载加速了煤体损伤破坏的进程,煤体破坏时的峰值应力和体积扩容受控于围压卸载的程度,控制轴压加载速率和围压卸载程度可控制煤体破坏时的峰值应力和体积变形。生产实践中,应结合煤岩体的采动力学行为特征,确定合理的推进速度并加以控制,以保证回采巷道与采场围岩的稳定性。更多还原

【Abstract】 In order to obtain the characteristics of mining-induced mechanical behavior for coal and rock mass under different advancing speed,the vertical stress and horizontal stress under different advancing speed were simulated through axial compression and confining pressure respectively,and the mining-induced mechanical behavior of coal and rock mass was simulated by using the way of increasing axial compression and dropping confining pressure. At the same time,the mining-induced mechanical behavior of coal and rock mass under different advancing speed was studied by using the combined methods of numerical simulation and engineering practice. The results showed that under the conditions of the same unloading rate of confining pressure,the peak strength,axial strain and transverse strain of coal body present an increasing trend with the increasing loading rate of axial compression( advancing speed). The larger axial strain and transverse strain appear in the peak phase,which presents a certain ductility,and the destruction form has the plastic characteristic. The volume of coal body is always in a state of expansion and deformation under the combined effect of axial loading and confining pressure unloading,and the process of coal body damage is accelerated by confining pressure unloading. The peak stress of destruction and volume expansion are controlled by unloading degree of confining pressure,and the peak stress and volume deformation can be controlled by controlling the loading rate of axial compression and unloading degree of confining pressure. Reasonable advancing speed should be determined and controlled combining with the characteristics of mining-induced mechanical behavior for coal and rock mass in production practice,so as to ensure the stability of mining roadway and surrounding rock in stope.更多还原