锚杆支护合理预紧力的确定及优化

Determination and optimization of reasonable preload force for anchor rod support

以黄陵二号煤矿二盘区211回风巷与420胶带巷为工程背景,采用理论分析、锚杆预紧扭矩与预紧力转化试验、井下现场试验相结合的方法,探讨了某矿煤巷支护锚杆合理预紧力的确定。试验研究表明,锚杆预紧力与螺母预紧力矩成正比,且取决于系数k,k值越大,减摩效果越好,相同的预紧扭矩对应的锚杆预紧力越大;通过提高螺母预紧力矩和转换系数k值可以增大锚杆预紧力,而减摩垫片可使锚杆预紧力显著提高,且预紧扭矩越大,减摩垫片的作用越明显。对比井下试验发现,矿用锚杆预紧力转化系数低,建议预紧扭矩为400 N·m,转化后预紧力为32~72 kN,预紧力大,支护效果较好。

In this paper,taking the 211 return air roadway and 420 belt roadway in the second panel area of Huangling No.2 Coal Mine as the engineering background,using theoretical analysis,anchor preload torque and preload force conversion experiments,underground field tests and other methods,the determination of the reasonable preload force of the anchor rod of a mine coal roadway is discussed.The experimental study shows that the anchor preload force is proportional to the nut preload torque,and depends on the coefficient k,the larger the k value,the better the friction reduction effect,and the greater the anchor rod preload force corresponding to the same preload torque.Increase the anchor preload by increasing the nut preload moment and the conversion coefficient k value,the friction reduction gasket can significantly increase the preload of the anchor rod,and the greater the preload torque,the more obvious the role of the friction reduction gasket.Compared with the downhole test,it is found that the preload conversion coefficient of the mine anchor rod is low,and the recommended preload torque is 400 N·m,and the preload after conversion is 32 ~ 72 k N,with large preload and good support effect.