深井大跨度切眼施工方式研究

Analysis of Excavation Method of Large Span Open-Off Cut in Deep Mine

为了掌握大跨度切眼不同成巷方式对巷道围岩稳定性的影响,本文结合淮南谢一矿深井大跨度切眼支护难题,采用数值模拟研究了一次成巷、二次成巷与三次成巷3种开挖方式下切眼围岩变形特点与应力分布特征,研究结果表明:一次成巷、二次成巷底鼓小,但顶板下沉量大,且切眼周围应力集中程度很高,塑性区范围较大,三次成巷开挖方式切眼顶板下沉量较小、围岩塑性区较小,三次成巷更有利于围岩稳定.在谢一矿511C(3)大跨度切眼(8.4 m)采用三次成巷方式进行了现场试验,采用高强度锚杆锚索组合支护系统维护深井大跨度切眼,矿压观测表明,围岩变形在控制范围内,锚网支护结构可靠.

In order to master the effect of construction condition on stability of surrounding rock of large span open-off cut, we numerically simulated the characteristics of stress distribution and surrounding rock deformation of the open-off cut under the construction condition of oncetunneling, twice tunneling, and three-times tunneling so as to solve the problem of large span open-off cut in deep mine of Xieyi coal mine in Huainan. The result shows that 1） both the once tunneling and twice tunneling have a small floor heave and a great roof convergence, so the stress in the area surrounding open-off cut is highly concentrated, forming a large plastic area in surrounding rocks; and 2） the three-times tunneling has a small roof convergence and a small plastic area in surrounding rocks, so it is favorable for the stability of surrounding rocks. According to this excavation method in large span open-off cut （8.4 m） of 511C（3） working face, the support system of high strength bolt and anchor was used to maintain the stability of open-off cut, making the roadway deformation be controlled within the allowable range and the structure of bolt-net supporting system reliable.