切槽煤岩试样裂纹扩展颗粒流分析

Analysis on particle flow of crack propagation in slotting coal and rock sample

为了探讨水射流增渗情景下不同切槽参数对煤体损伤及裂纹扩展的影响,采用颗粒流PFC2D软件建立单切槽、双切槽煤样参数模型,模拟单轴载荷作用下切槽面与载荷夹角为90°、45°和0°情况下试样损伤过程,对比分析全应力-应变过程中煤体裂纹分布、裂纹数量及内部摩擦能的变化。模拟结果表明:进入塑性变形阶段煤体裂纹快速发育,内部摩擦能伴随增大,裂纹集中分布于切槽两端处,多切槽布置将引导裂纹定向发育扩展;增加切槽面数量、增大切槽面与载荷应力夹角能够降低煤体裂纹发育阈值,促进煤体裂纹扩展;水射流切槽工艺布置设计应选择切槽面与主应力夹角为45°情况,避免切槽内错夹角为0°情况。

In order to investigate the effect of different slot parameters on coal damage and crack propagation under water jet technology,the single slot and double slot coal sample parameters model were established by PFC^2D software. The damage process of sample under the condition of 90°,45° and 0° angle under the uniaxial load were simulated,and the total stress-strains were compared and analyzed. The distribution of cracks,the number of cracks and the internal friction energy in coal were also discussed. The simulation results show that the fast development of coal crack in the plastic deformation stage were that the internal friction can increase with the increase of the internal friction,and the cracks were distributed at both ends of the cutting slot. The layout of the multi slot would guide the development of the crack orientation,and the increase of the number of slot surface and the angle between the increase slot size and the load stress could reduce the threshold of the coal crack development. The design of water jet slotting process layout should choose the angle between the slot surface and the main stress as 45°,and avoid the wrong angle of 0° between the slots.