超浅埋暗挖矩形隧道设计

Design of Undercut Rectangular Tunnel with Super-shallow Overburden

南京地铁鼓楼站D2出入口通道，覆土厚仅1．3—1．6m，且通道上方有电缆线、给水管等。结合该工程对明挖顺作法和浅埋暗挖法两种方案进行了比较，拟采用浅埋暗挖法。介绍了其结构设计及计算，施工方法及措施要点。该通道已顺利完成，既未影响中央路的正常交通，而且地面沉降、结构变形、工期、防水均满足要求，且其设计施工经验已成功用于其他车站出入口通道的施工。

The overburden of D2 access tunnel of Gulou Station of Nanjing Metro is only 1.3 - 1.6 m. Above the access tunnel, there exist power cables and water supply pipes. Regarding the construction of the tunnel, comparisons are made between open cut method and undercutting method with shallow overburden and the latter is determined to be adopted. The paper presents the structural design and calculations of the access tunnel, as well as the construction method and the fundamental technical measures taken. The construction of the access tunnel has already been successfully completed, with the traffics on Zhongyang road having not been interfered and the ground surface settlement, structural deformation, construction schedule and waterproofing of the tunnel having met the relevant requirements. The successful experience of the access tunnel has already been used in the construction of the access tunnels of other Metro stations.