侵入蚀变岩隧道大变形控制技术研究

针对侵入蚀变岩隧道施工期洞周变形过大、施工功效低等问题,以玉磨铁路安定隧道为工程依托,采用现场调研、数值模拟等方法研究侵入蚀变岩隧道大变形控制措施,分析掌子面喷砼封闭和拱脚大直径锁脚锚管对隧道洞周变形的控制效果;探讨隧道施工功效降低原因,并提出改进方法。研究表明:(1)采用掌子面喷砼、?76大锁脚锚管、加大预留变形量三种措施对隧道洞周变形可进行有效控制且效果明显。(2)掌子面喷砼措施对洞周水平位移控制更为显著,而锁脚锚管对拱顶沉降的控制较为明显。(3)导致隧道施工功效降低的主要原因为围岩级别变化与不良地质频繁出现,提出增设斜井辅助施工通道和变更钢拱架支护方案两种措施,极大提高了隧道施工功效。

Research on Large Deformation Control Technology of Invasive Altered Rock Tunnel

Based on the excessive deformation and low construction effect during the construction of intrusive altered rock tunnel,the paper studied the control measures for large deformation of the tunnel by the method of the field research and the numerical simulation,analyzed the control effect of using concrete spraying measures of the tunnel face and large-diameter locking anchor pipe on the deformation around the tunnel,and discussed the reasons for reduction of tunnel construction efficiency and proposed the improving methods.The study shows that:(1)we can adopt the measures of tunnel face concrete spraying,?76 large locking anchor pipe and increasing the reserved deformation amount,and the site control effect is obvious.(2)The concrete spraying measures of the tunnel face more significantly control the horizontal displacement around the tunnel,and the measures of locking the foot anchor pipe significantly control the settlement of the arch.(3)The main reasons for the reduction of tunnel efficacy are the change of surrounding rock level and the frequent occurrence of bad geology.Two measures are proposed:for adding inclined well auxiliary construction channel and for the change of steel arch support scheme,which greatly improve the effect of tunnel construction.