某矿5~#煤层软岩巷道锚杆锚索联合支护方案

Integrated Supporting Scheme of Anchor Rob and Anchor Rope of Roadway with Soft Surrounding Rock in 5~# Coal Seam in a Coal Mine

某矿5#煤层围岩层岩性较软,可塑性较强,遇水有膨胀现象,该煤层已掘进的巷道均见有底鼓现象,极易造成巷道变形。结合该矿巷道变形破坏的实际情况以及巷道矿压监测数据,分析了巷道变形破坏特征,认为棚式金属支架支护作为一种被动支护形式,难以发挥围岩的支撑作用,且支护成本较大,软岩巷道的支护原则应为避开回采工作造成的应力集中带或构造应力集中带,充分利用围岩的自稳性,提高巷道帮部的支护强度。在此基础上,结合FLAC数值模拟分析方法,设计了以锚网索支护为核心的支护方案,巷道优先采用全长锚固锚杆,支护范围宜相应增大,选取长度大的锚杆、锚索对巷道围岩进行联合支护。研究表明:该煤层软岩巷道锚杆、锚索联合支护的最优参数为巷道顶板采用高强度小孔径全锚索支护形式,锚索直径为17.8 mm,锚索预紧力不宜小于135 k N;巷道帮部采用自旋式全长锚固支护形式,以改善锚杆的整体受力状况,锚杆长度应相应增加,锚杆直径为22 mm,长度为3 500 mm,锚杆(索)间排距为800 mm;巷道顶帮均采用高强钢带或槽钢和金属网护表,确保巷道浅层围岩稳定。

The lithology of the surrounding rock of 5#coal seam of a coal mine is soft,the plasticity characteristics of the surrounding rock is significant,besides that,its inflation features is also obvious under the action of water. The floor heave phenomenon is widely existed in the excavated roadways in the coal seam,which can easily cause roadway deformation. Based on the actual situation of roadway deformation and the roadway pressure monitoring data,the deformation and failure characteristics of the roadways is discussed. The results indicated that the supporting effect of the roadway surrounding rock can not be displayed effectively by adopting the scaffolding metal supporting method that is a typical passive supporting form,besides that,its supporting cost is high. The supporting principle of soft rock roadway can be summarized as the stress concentration zone or tectonic stress concentration zone caused by stoping operation should be avoided effectively,the supporting strength of roadway ＇s sides should be strengthened as soon as possible by making full use of the self-stability of surrounding rock of roadway. Based on the above analysis results,combing with the FLAC numerical simulation method,the supporting scheme that is mainly for anchor rope supporting form is designed,the full-length anchor rob should be used for supporting the roadway,the supporting scope can be expanded accordingly,the surrounding rock of roadway can be supported by the integrated application of longer anchor rob and anchor rope. The study results show that the optimal parameters of the integrated supporting scheme of the soft rock roadway in 5#coal seam can be described as the roof of roadway can be supported by using the full anchor rope supporting form with high strength and small aperture,the diameter of anchor rope is 17. 8 mm,pre-tightening force anchor rope should not be less than 135 k N; the roadway＇s sides can be supported by adopting the spin type full-length anchorage supporting form,so as to improve the overall stress state of anchor rob,the length of anchor rob should be increased correspondingly,the diameter of anchor rob is 22 mm,and its length is 3 500 mm,the density of anchor rob（rope） is 800 mm; the roadway roof corner can be supported by using high strength steel belt or channel steel and metal mesh,to ensure the stability of shallow surrounding rock of roadway.The integrated supporting scheme of the roadway with soft surrounding rock can provide some reliable reference for safety excavating of the roadways with soft surrounding rock in coal mines.