高应力大断面煤巷支护技术研究

Study on supporting technique of high stress and large section coal roadway

为解决陕西省某矿辅助运输大巷强烈大变形、维护极差的难题,采用数值模拟方法,重点研究了不同构造水平应力、不同断面尺寸条件下巷道围岩的变形特征、塑性区及最大主应力分布情况。研究结果表明,巷道底板和两帮受开挖扰动最为明显,围岩变形量最大,且随着水平应力和巷道断面尺寸不断增大,围岩破坏范围不断扩大,且底板和帮部围岩破坏范围和围岩变形量最大。在此基础上,提出了巷道二次补强加固技术,即首先实施高强锚网索支护,待围岩产生一定变形后,采用预应力锚索对巷道围岩变形突出部位实施二次补强加固,重点加强巷道帮部及底角部位,避免巷道因局部大变形导致的整体失稳。现场试验结果表明,该支护技术应用后,巷道两帮移近量、顶底板移近量分别为121,185 mm,巷道维护效果良好。

In order to solve the problem of large deformation and poor maintenance of the auxiliary lane in a mine in Shaanxi Province,the numerical simulation method was used to study the deformation characteristics,the plastic zone and the maximum deformation of the surrounding rock under different structural horizontal stresses and different section sizes stress distribution. The results show that the excavation disturbance is most obvious in the roadway floor and two sides where the maximum deformation are largest. With the horizontal stress and the section size of roadways increasing,the scope of rock damage is increasing,and the damage scope and deformation of surrounding rock in the floor and two sides are largest. On this basis,the secondary reinforcement technique was put forward,firstly,the implementation of high strength bolt net support is completed,then with a certain amount of deformation being taken place; secondly,implementing the secondary reinforcement for the deformation protrusion parts by using the prestressed anchor cables,focusing on reinforcing the roadway sides and floor to avoid the whole roadway instability because of local large deformation. The field test shows that the convergence between the two sides and the top and bottom after the new support technology implemented for three moths are 121 mm,185 mm,respectively,which proves that the roadway was well maintained.