Rectangular Pipe Jacking for Complex Urban Crossings

Crossing conditions and construction priorities

Dashou's rectangular pipe jacking experience includes navigable waterway crossings, major road crossings, close-clearance construction near buildings and utilities, and projects in water-bearing sandy strata. Construction planning addresses the specific combination of soil cover, groundwater conditions, existing structures, and launch and reception constraints.

Zhuowen Road Crossing Beneath the Chuanyang River, Shanghai

The project used a 10.06 m × 5.26 m rectangular jacking section for two drives, each 106.2 m long, beneath the approximately 60 m-wide Chuanyang River and its flood-control walls. Along the river crossing, water depth ranged from approximately 0 to 4.5 m and soil cover from approximately 5.20 to 11.04 m; cover at the launch and reception ends was approximately 11.0 to 11.5 m. Construction priorities included buoyancy control, seepage prevention, prevention of uncontrolled soil and water inflow and slurry escape, and excavation-face stability under varying cover.

Hong Kong KT5B Project

The project used a 10.8 m × 7.5 m rectangular jacking section over a drive length of 79.308 m beneath Prince Edward Road East. The surrounding underground environment included municipal utilities, viaduct piles, and mini-piles associated with elevated road infrastructure. The project involved coordinating large-section jacking with existing transport infrastructure and a constrained site.

Fuquan Road Pedestrian Passage, Shanghai

The passage used a 9.8 m × 6.3 m rectangular jacking section over 210 m, running longitudinally beneath Fuquan Road with approximately 3.766 to 5.816 m of soil cover. It passed close to the Ctrip building basement, with approximately 1.5 m horizontal separation and 4.97 m vertical separation. Clearance to a 1,500 mm-diameter stormwater pipe was approximately 0.91 m, and ground improvement was undertaken to protect this pipe. The works also included pipe-wall grouting during jacking.

Jianning West Road Tunnel Extension, Nanjing

The third construction section used an 11.35 m × 7.5 m rectangular jacking section, with approximate drive lengths of 275 m for the left alignment and 249 m for the right. Soil cover was approximately 12.5 m on the left and 13.2 to 17.8 m on the right. The drives passed through water-bearing silty sand and interbedded silt and silty sand, beneath roads, a moat, and existing box culverts, and close to buildings and heritage structures. Clearances included approximately 7.8 m and 10.2 m to the box culverts, approximately 6.1 m to the timber piles of the Shizishan city-wall remains, and a minimum horizontal clearance of approximately 5.2 m to nearby buildings and structures.