China Railway 14th Bureau

The Shield Tunnel on the Left Line of Jianning West Road Cross River Channel Achieves Connection

The Jianning West Road River Crossing Tunnel is the closest river crossing tunnel to the Nanjing Yangtze River Bridge, and is an important channel connecting the main city of Jiangnan and the Jiangbei National New Area. The left tunnel has a total length of 2674 meters, including a shield tunnel section of 2349 meters, a segment outer diameter of 14.5 meters, and a shield machine excavation diameter of 15.07 meters.

Shield tunneling passes through various complex geological conditions such as strong permeable sand layers, uneven composite layers of soft and hard, large width fault fracture zones, and full section silty clay layers. The maximum water depth of the crossing section is 55 meters, and it can withstand a maximum water and soil pressure of 7.7 bar. The fault fracture zone at 310 meters has a soft upper layer and a hard lower layer, with a maximum rock compressive strength of 125 MPa. The minimum soil cover thickness at the bottom of the river is only 10.55 meters.

Project Use Herrenknecht φ A 15.07-meter slurry shield tunnel is equipped with four oil and grease tanks, 20 grease injection points in one tank, and four Gurik C68 pneumatic diaphragm pumps.

The entire line has 1175 rings, and WR89NG shield tail sealing grease is used throughout the entire process. The shield tail sealing is in good condition, and there is no water leakage. The amount of grease used throughout the line is stable.

When the shield tail of the Tongtong rear shield was launched, our technical personnel rushed to the scene at the first moment to check the condition of the shield tail brush, and the steel wire brush of the shield tail brush was normal. The overall tail brush still maintains a certain degree of angular elasticity, and there is still some grease inside the included angle part, without any slurry agglomeration.

Sincerely thank China Railway 14th Bureau Big Shield Company for providing us with this cooperation platform, and look forward to further cooperation with China Railway 14th Bureau Big Shield Company in various fields of tunnel development in the future!