Since in soft surrounding rock zone, it is difficult to construction of bi-arch tunnel, and no experience we can learn from.

在软弱围岩地区，双连拱隧道的施工具有极大的难度，没有可以借鉴的经验。

youdao

Since in soft surrounding rock zone, it is difficult to construction of bi-arch tunnel, and no experience we can learn from.

在软弱围岩地区，双连拱隧道的施工具有极大的难度，没有可以借鉴的经验。

youdao