回采工作面片帮机理及超前预注化学浆体锚杆控制技术

Mechanism on rib spalling and its prevention technology for chemical-paste bolt with advance grouting

煤壁片帮是综采工作面常见而又不能有效解决的问题.依据极限平衡理论,建立了煤壁片帮的物理力学模型,推导出了回采工作面煤壁片帮的宽度及护帮板对煤壁支护力的表达式,分析了煤壁片帮的影响因素.根据现场调研和分析,可将煤壁片帮机理分为拉伸式、剪切式和复合式3种类型.片帮受竖向裂隙及煤层结构控制.为了加固煤壁且保证工作面正常推进,提出了在工作面上下巷灌注化学浆体材料,超前回采工作面对煤壁进行化学浆体锚杆加固的方法.现场实践表明,化学浆体锚杆能够强化煤壁,有效降低其破碎区及塑性区的宽度,显著减小煤壁片帮几率及规模;化学浆体锚杆具有易切割、易分选、无污染的特点,具有良好的物理力学性能,对工作面的正常生产无干扰,取得了较好的技术经济效益.

Rib spalling is often encountered in a fully-mechanized mining face,but this problem has not being solved.According to limit equilibrium theory,a physical mechanics model for coal face rib spalling was established.An expression on width of rib spalling and face guard force were deduced.Influence factors of rib spalling were analyzed.According to field observation and analysis,spalling mechanics might be classified as a tension,a shear and their combined types,which are dominated by vertical fractures and coal seam structures.In order to reinforce the wall but not affect the normal mining,a new technology operated at advanced gate roads was proposed,aiming to establish prevention technology for chemical-paste bolts with advance grouting.The strength of a rib can be reinforced by chemical-paste bolts.Width fracture and plastic performance can be reduced effectively.Rib spalling probability and scope can be decreased with this bolts.The chemical paste anchor could be characterized with easy cutting,easy separation,no pollution,good physical and mechanical performance,and no interference with normal mining.The technology is benefit to high production and high efficiency,and the economic benefit is remarkable.