虹桥商务区供能管沟工程的结构设计

虹桥商务区核心区一期面积约1.4 km²,供能管沟工程全长3 506 m。管沟结构设计采用内径4.2 m钢顶管或4 m混凝土顶管结合明挖法现浇箱涵方案。采用河道压载措施解决顶管浅覆土过河问题;采用高压旋喷加固保护减小顶管穿越对高架桩基的影响;设计承插式中继间协调钢顶管段与能源站结构间的差异沉降。对顶管井及一般明挖段小尺度基坑采用较规范标准降低基坑安全等级的进行优化设计;对顶管井结构进行三维分析,大直径顶管洞口依据有限元计算结果进行配筋加强;管沟在地块接口处预设临时封堵墙、变形缝及顶板挡土墙以便后续地块衔接。结合相关工程经验及规范要求,确定了管沟结构的保护标准。

Structure Design of Energy Supply Tunnel for the Hongqiao Business District

The core zone area of the Hongqiao business district is about 1.4 km² and the length of energy supply tunnel is 3506 m. Steel jacking pipe with inner diameter of 4.2 m and concrete jacking pipe with inner diameter of 4.0 m and cast-in-situ concrete box culvert are used in the tunnel structure design. The ballasts are placed on river bed as the jacking pipe is passing through the river with shallow overburden; the jet-grouting piles are designed to protect overpass pile foundation as the jacking pipe is passing; Spigot joint of steel jacking pipe is adopted to adjust the settlement difference between the steel pipe segment and the energy station structure. The excavation pits of pipe jacking work well and normal tunnel section having small scale characteristic and lower safety degrees are used to optimize excavation design; The work well structure is analyzed by 3D modeling and the strengthening bars of large opening are determined by using FEM results; The temporary wall, deformation joint and retaining wall on tunnel roof are prepared for block connecting. Combined with the experience and regulation of related engineering, the standards for the protection of pipe trench structure are determined.