温州雁荡山地区铁路隧道施工地质问题探讨

塌方、掉块、围岩整体失稳等是隧道施工中要解决的主要难点问题。浙江雁荡山地区的铁路客运专线和货运专线两个项目分布有28 km双线隧道、6.4 km单线隧道。各隧道所穿越的山体地形、岩石地层等存在一定差异,围岩稳定性、施工工况具有丰富性和多样性。雁荡山地区工程地质条件较好,但在隧道进出口、浅埋地段,特别是风化层深厚地段,隧道施工易发生拱顶塌方冒顶;加之围岩压力过大、隧底软化,地基承载力不足,易导致围岩整体变形下沉。本文结合雁荡山地区火山运动及成岩背景,分析了该地区岩体结构、隧道工程地质条件,并结合隧道施工中出现的问题提出改进隧道设计、施工、现场管理的建议,可为本地区以后隧道工程的勘察、设计及施工提供参考。

Discussion on the Key Issues of Railway Tunnel Construction in Yandang Mountain Area of Wenzhou

Collapse,block drop,and overall instability of surrounding rock were the main difficult problems to be solved in tunnel construction.The two railway passenger dedicated lines and freight dedicated lines in the Yandang Mountain area of Zhejiang were distributed with 28 kilometers of double-track tunnels and 6.4 kilometers of single-track cargo tunnels.The tunnels had certain differences in traversing mountain topography and rock strata.The construction conditions show a relatively rich diversity.The engineering geological conditions of the Yandang Mountain area were well,but at the entrance and exit of the tunnel,shallow-buried sections,especially sections with deep weathered layers,tunnel construction was prone to vault collapse and roof fall;in addition,the surrounding rock pressure was too large,the tunnel bottom was softened,and the foundation bearing capacity was insufficient,it was easy to cause the overall deformation and sinking of the surrounding rock.Based on the volcanic movement and diagenetic background of the Yandang Mountain area,this paper analyzed the rock mass structure and tunnel engineering geological conditions in this area,and put forward suggestions for improving tunnel design,construction,and site management for the problems that occurred during tunnel construction.It could provide reference for the survey,design and construction of future tunnel projects in this area.