乌鞘岭特长隧道软弱围岩大变形特性研究

Study on the large deformation characteristics of the soft rocks in Wushaoling tunnel

乌鞘岭特长隧道全长20050m,是我国目前正在修建的国内最长的单线铁路隧道.隧道施工中发生了严重的围岩大变形,主要表现为隧道中部岭脊地段F4～F7断层构成的'挤压构造带'在深埋高地应力条件下的软弱围岩大变形,拱顶最大下沉及侧壁最大水平收敛变形量均达1000mm以上,导致初期支护开裂破坏并严重侵入衬砌净空等,不得不将初期支护全部或部分拆除重做,再施作二次衬砌.文章对隧道区域工程地质环境、软弱围岩变形力学特性及初期支护破坏规律、围岩变形的影响因素等进行了分析研究,并讨论了隧道围岩加固、初期支护预留变形量与二次衬砌施作时机等问题.

Wushaoling tunnel is the longest single line railway tunnel in China with the length of 20.50 km and is now under construction. Serious deformations occurred in the surrounding rock during construction in the mid part of the tunnel called 'extruded structure zone' caused by faults F 4 and Fault F 7. The settlements of the arch crown and the horizontal deformations of side walls reached 1 000 mm and over, the primary supports had to be all or partly removed and reconstructed due to these serious deformations. This article analyzed the regional engineering geological environment, the mechanical characteristics of soft rock deformation, the mechanism of the destruction of primary supports and the factors affecting rock deformations etc. The reinforcement of surrounding rock, the reserved deformation for primary supports and the time for the construction of the secondary lining were studied accordingly.