双层小导管在浅埋暗挖隧道施工中的应用

结合北京地铁崇—东区间隧道采用的浅埋暗挖施工技术,介绍了双层小导管的工艺原理及施工工艺。工程应用结果表明,通过采取双层超前导管,实现“多钻孔、多分层、小流量、低压力、低流速”的注浆加固方式,具有提高围岩自稳能力、降低地层水的渗透和控制地表沉降等优点,有效保障了地表建筑物和地下管线在地铁隧道施工过程中的安全。

Application of technology of two-layered ductules in urban shallow-cover and close-cut tunnel

The technological principle and construction technique of pre-grouting reinforcement by two layered ductules were introduced on the base of its construction in the shallow-cover and close-cut subway tunnel located in the Song-Dong zone in Beijing.The technique of pre-grouting reinforcement by two-layered ductules was successfully applied by the methods of more drilling bores,more layers,little flow,low pressure and low flow velocity.The results showed that there were some strongpoints for this technology,such as improvement of self-steady ability,lower seeping water and control settlement of stratum.The building and underground pipelines near the subway tunnelling were effectively protected during the construction.