双联拱隧道洞口明挖段改暗挖施工技术

Mined excavation replaced cut-and-cover for the portal section of a double-arch tunnel

双联拱隧道跨度较大,造价相对较高,设计时为节省造价,洞口石方明挖量较大。以明挖代替暗挖,这在施工干扰小、环保要求小的地方是可行的,但在施工干扰较大,如建筑物密集、靠近道路等地方就不合适。因此,要根据实际情况选择明挖与暗挖,以图达到优化设计及施工的目的。

The portal section of Yinzishan double-arch tunnel was planned to construct by using cut- and-cover method. However, considering the large amount of excavation by open-cut, the disturbance of traffic on a road nearby, the existence of surface buildings and especially environmental protection, mined excavation of this section was adopted instead of open-cut.