Project name: Nanjing Weisan Road River Crossing Channel
Construction unit: CCCC Tunnel Bureau
Shield model and diameter: CCCC Tianhe 14.93m slurry shield
Product used: CONDAT WR89; CONDAT HBW; CONDAT EP2

Project overview:

Weisan Road River Crossing Tunnel Project is located at 5km upstream of Nanjing Yangtze River Bridge, connecting Nanjing Jiangnan main urban area and Jiangbei Pukou New Area. The Jiangbei connecting line is located in Puzhu Road, Pukou District, Nanjing City, crossing the Yangtze River along the Zhihe Road. The current situation along the line is dominated by farmland. Some civilian houses and factories are distributed on both sides of Puzhu Road and Zhihe River. The Weisan Road river crossing channel adopts the 8-lane "X" shaped shield tunnel scheme, with a shield diameter of 14.93m. The S-line shield tunnel of the Project is 4140m long, and the overburden thickness is 10.8-51.5m. The N line shield tunnel is 3433m long, and the overburden thickness is 9.8~51.5m.

Surrounding environment:

Daxing Cross River, classic buildings along the Jiangbei River, the Yangtze River levee in Pukou section, the former site of Xinhua Shipyard, Meizizhou Flood Control Dike, Yulin Shipyard, the Yangtze River levee in Jiangnan, and residential houses along the Dinghuaimen Gate.

Project characteristics and difficulties:

(1) Super large section: excavation diameter is nearly 15m
(2) The geological conditions are complex: it crosses a variety of strata, of which there are about 800m silty sand strata in the middle section of the river, and some of them enter the rock strata in full section. Part of it is the upper pebble layer and the lower sandstone layer

(3) High water pressure: the maximum hydrostatic pressure reaches 0.77Mpa, which is the highest in domestic shield tunnels
(4) Large earth pressure: the maximum buried depth is 66M
(5) Length of shallow buried section: the shallow overburden section in the river is about 1000 m.