山西省小浪底引黄工程7#支洞控制主洞塌方处理方案

Scheme to Treat Collapse of the Main Tunnel Controlled by NO.7 Access Tunnel in the Xiaolangdi Yellow River Diversion Project of Shanxi Province

山西省小浪底引黄工程施工7#支洞控制主洞掘进至掌子面桩号25+531处,准备安装顶拱钢拱架时,掌子面发生坍塌,钢拱架顶拱右侧变形严重,右上侧出现塌方空腔体。根据实际情况,采取了在该段制作止浆墙,进行止浆墙注浆加固、搭设大管棚、辅助小导管、掌子面超前预注浆、钢拱架挂网喷锚、浇筑混凝土边墙的联合支护方式,及时有效实施险情控制,并成功通过该洞段。

In the process to excavate the main tunnel controlled by NO.7 access tunnel in the Xiaolangdi Yellow River Diversion Project of Shanxi Province,when the driving face of the main tunnel reached the position of the chainage25 ＋531 and the work was prepared to install the top arch steel rack,a collapse accident on the driving face suddenly occured,the right side of the top arch steel racks were deformed severely and a collapse cavity at the upper right side had appeared. In view of the actual situation,a union support was adopted to effectively control the danger situation in time.Its contents include：constructing grout stop walls,using the grout-injecting measure to consolidate grout stop walls,building large pipe sheds with small pipes,advanced pregrouting on the driving face,hanging the steel mesh and anchoring shotcreting concrete on the arch steel racks and placing concrete side walls. Because of adopting these measures,the construction task of passing this tunnel section was finished successfully.