高侧压软岩巷道破坏机理及控制技术研究

Study on Failure Mechanism and Control Technology of Soft Rock Roadway with High Lateral Pressure

为揭示高侧压软岩巷道底鼓和侧鼓的机理,以陕西某铜矿为工程背景,从岩体性质、地应力分布、巷道形状和支护条件等方面进行了理论分析和FLAC3D数值分析。结果表明:巷道底鼓和侧鼓的根本原因是围岩软弱破碎和水平地压大,顶板矢跨比为0.33、底板矢跨比为0.2、侧帮矢跨比为0.09时对控制巷道变形最为有利;与直墙平底三心拱相比,马蹄形巷道顶板下沉量下降为6.8%,底鼓量下降为20.7%,侧鼓量下降为10.7%;与不耦合支护相比,耦合支护使巷道底鼓量降低34.1%,侧鼓量降低41.4%;与底板不支护相比,底板支护底鼓量降低20.4%,侧鼓量降低15.5%。在优化巷道形状的基础上,采用"喷锚网+全断面钢架+架后袋装充填圈"的联合支护方式,顶底板移近量为14.5mm,两帮移近量为32mm,能够保证巷道稳定。

In order to reveal the mechanism of floor heave and side heave in soft rock roadway with high lateral pres sure,theoretical analysis and FLAC3D numerical analysis are carried out from the aspects of the nature of rock mass,in-situ stress distribution,roadway shape and support conditions,taking a copper mine in Shaanxi Province as an engineering back ground. The results show that the floor heave and side heave are basically caused by the weakly broken surrounding rock and high horizontal ground pressure. The best favorable conditions for controlling the deformation of surrounding rocks are the roof rise-span ratio at 0.33,floor rise-span ratio at 0.2, and sides rise-span ratio at 0.09. Compared with the straight-wall flat-bot tom three-center arch,the roof subsidence of horseshoe-shaped roadway decreases by 6.8%,the floor heave decreases by 20.7%,and the side heave decreases by 10.7%. Compared with uncoupled support,the coupling support reduces the floor heave by 34.1%,the side heave by 41.4%;Compared with the roadway without floor support,the roadway with floor support reduces the floor heave by 20.4% and the side heave by 15.5%. On the basis of optimizing the shape of the roadway,the com bined support method of "shotcrete anchor net + full-section steel frame + bag filling ring behind support" is adopted with the roof-to-floor convergence at 14.5 mm,and the two-side convergence at 32 mm,which can ensure the stability of the roadway.