切顶卸压技术在降低巷道围岩变形中的应用

Application of Roof Cutting and Pressure Relief Technology in Reducing the Deformation of Surrounding Rock in Tunnels

3505胶带顺槽与邻近的3504综放工作面轨道顺槽间留设20m保护煤柱,且在采面回采前即完成掘进,3505胶带顺槽受3504综放工作面采动压力影响,导致巷道围岩变形量大甚至有冒顶风险。为此,提出采用切顶卸压技术降低3504综放工作面回采对3505胶带顺槽影响,改善3505胶带顺槽受力环境。结合现场情况,采用理论计算以及工程类比法确定切顶卸压技术参数,具体为沿着3504轨道顺槽靠近采面帮向按75°倾角向顶板施工15 m深切顶钻孔、切顶钻孔间距为3 m,钻孔孔底9m装入18卷规格d60 mm×480 mm煤矿许用三级乳化炸药,用黄泥封孔6 m。现场应用后,3504综放工作面回采期间3505胶带顺槽顶底板、两帮围岩增加量分别为10.1、7.2 mm,变形量很小,现场应用取得较为显著的围岩变形控制效果。

A 20 m protective coal pillar is left between the 3505 belt trough and the adjacent 3504 fully mechanized top coal caving face track trough,and excavation is completed before the mining face is recovered.The 3505 belt trough is affected by the mining pressure of the 3504 fully mechanized top coal caving face,resulting in large deformation of the surrounding rock of the roadway and even the risk of roof fall.To this end,it is proposed to use the top cutting and pressure relief technology to reduce the impact of mining on the 3505 belt trough in the 3504 fully mechanized caving face,and improve the stress environment of the 3505 belt trough.Based on the on-site situation,theoretical calculations and engineering analogy methods are used to determine the technical parameters of top cutting and pressure relief.Specifically,a 15m deep top drilling is carried out along the 3504 track along the groove near the mining face,with a 75°inclination angle towards the roof.The spacing between top cutting drilling holes is 3m,and the bottom of the drilling hole is 9m,and 18 rolls of d60 mm×480 mm specifications are loaded into the hole coal mine is allowed to use Grade III emulsion explosives,and the hole is sealed with yellow mud for 6 meters.After on-site application,during the mining period of 3504 fully mechanized top coal caving face,the increase of 3505 tape along the top and bottom of the groove,as well as the two sides of the surrounding rock,were 10.1 and 7.2 mm,respectively,with very small deformation.The on-site application achieved significant deformation control effects on the surrounding rock.