江肇高速公路毛毡岭隧道洞口浅埋段施工

江肇高速公路毛毡岭左线隧道肇庆端洞口V级围岩超浅埋且为碎石土与全一强风化泥岩的软弱围岩,针对其实际情况,施工中遵循“早进晚出”的原则提前进洞,减少了隧道施工对烂柯山自然保护区的环境破坏。隧道进洞采用了长管棚、小导管注浆等措施加固岩体,洞内采用双侧壁导坑法施工方法减少了隧道一次性开挖断面,施工中结合监控量测和超前地质预报及时调整支护参数,确保了隧道安全通过超浅埋段,满足了施工工期要求和对自然保护区环境的保护。

Construction of Extra-shallow-buried Portal Section of Maozhanling Tunnel of Jiangzhao Expressway

As the soft-weak surrounding rock at the entrance of Maozhanling left tunnel of Jiangzhao Expressway is mainly gravel and full-strong weathered mud stone,the construction principle of "early entering and late advancing" has been adopted to reduce the environmental damages of the Lanke Mountains Natural Protection Region.The large pipe-roof protection and small pipe grouting have been used to strengthen the surrounding rock,and two side drift method has been adopted to reduce each excavation sectional area.Supporting parameters have been adjusted timely through monitoring measurement and geological prediction.These have guaranteed the smooth construction of extra-shallow-buried section of the tunnel with demands of both construction time limit and the Natural Protection Region being met.