浅埋土质软岩隧道洞口段施工技术

在洞口遇断层、地层为第四系坡积层、含有黄土夹碎石、较厚腐植土且含水量丰富、两边边坡高及边仰坡围岩自稳性极差的条件下，如何形成进洞条件来加快施工进度是困扰工程进度的关键，重点介绍了在此种浅埋土质软岩中的隧道如何快速进洞的施工技术。

Construction Technology for Portal Section of Shallow-buried Tunnel in Soft Ground

The geological conditions of the entrance portal section of Laoyeling tunnel on Changchun - Huichun highway is extremely complex, where there exist fault zones and Quaternary clinosol that contains loesses, crushed stones, thick cumulose soil and rich water. Furthermore, the side slopes of the entrance portal section of the tunnel are high and the self-support ability of the ground of the side slopes and front slope of the tunnel is very poor. Therefore, it is of great importance to commence the tunnel excavation as soon as possible. The article presents in detail the measures taken so as to commence the excavation of the shallow-buried entrance portal section of the tunnel in soft ground.