极浅埋特大断面饱和黄土隧洞施工

邙山隧洞为南水北调中线一期工程穿黄隧洞盾构机接收洞,具有浅埋、开挖断面大、饱和黄土围岩等特点,合同中规定采用矿山法开挖,安全风险突出。施工中,采取双侧壁导坑法与分层降水、分层开挖相结合的混合工法,实施效果显著。

Excavation of Tunnels with Extremely Thin Cover and Super Large Section in Saturated Loess Soil

Mangshan Tunnel,the one to receive shield machine which passes through under the Yellow River in Stage I,middle route of south-to-north water diversion project,features thin cover,large excavating section and surrounding rock of saturated loess soil.In the contract,the tunnel is required to excavate by mining method which is with outstanding safety risks.Actually,combination of double side-wall heading excavation method,water reduction by layer and excavation by layer is applied and practical effect is outstanding.