"The first pile foundation was poured!" At 3:38 p.m. on April 9, the pouring of the first pile foundation for the north-bank main pier of the Nanjinguan Yangtze River Bridge was successfully completed.

"Affected by rainfall, we set up rain shelters in advance to ensure construction and successfully completed the pouring of the first pile," said Jiang Jin, chief engineer of the Yichang Chengxi Expressway Section 2 project of CCCC Second Harbor Engineering Co., Ltd. The first pile poured this time is 12 meters deep with a diameter of 3.4 meters; the concrete volume poured was 108 cubic meters, and the operation took 6 hours.

It is understood that the north-bank main pier of the Nanjinguan Yangtze River Bridge uses a separated pile cap with a group pile foundation, with a total of 32 piles ranging from 12 to 18 meters in depth. The north-bank main pier is adjacent to an ecologically sensitive area of the Yangtze River and is located on a 70-degree steep rock cliff, with a narrow site and hard bedrock, imposing extremely strong construction constraints. To protect the Yangtze River ecology, all pile foundations use the water-jet drilling (water mill drill) technique.

"The water mill drill technique produces no blasting vibration and has little impact on the environment. Facing hard bedrock, every inch of hole formation must be precisely controlled, and the construction difficulty far exceeds that of conventional techniques," Jiang Jin said. At present, the project has completed hole formation for 6 pile foundations and will carry out pouring operations successively, while excavation of the remaining piles is proceeding in an orderly manner.

The Nanjinguan Yangtze River Bridge is a controlling project of the Chengxi Expressway, with a main span of 1,200 meters and a deck width of 42.6 meters. It is the widest steel truss suspension bridge over the Yangtze River, with the north main tower 190 meters high and the south main tower 179 meters high. In addition to its traffic function, it also features a slow-traffic system with vehicular traffic on the upper level and sightseeing on the lower level.

On January 31 this year, pile foundation pouring construction was launched for the south-bank main pier of the bridge. With pile foundation pouring now officially beginning for the north-bank main pier, foundation construction for the main piers on both banks of the Nanjinguan Yangtze River Bridge is advancing in parallel, and the project construction has fully pressed the "fast-forward button."

The Yichang Chengxi Expressway starts in Xiaoxita Subdistrict, Yiling District, and ends in Gaojiayan Town, Changyang, adopting a two-way six-lane standard with a design speed of 100 kilometers per hour. After the project is completed and opened to traffic, it will connect with the Shanghai-Chengdu, Shanghai-Chongqing and Jiangnan Fanba expressways, transforming the expressway ring road of Yichang's central urban area from a "C" shape into an "O" shape and forming an intercity express corridor, thereby providing strong support for improving the comprehensive transportation system of the Three Gorges, serving the construction of national strategic projects, and helping Yichang build a national comprehensive transportation hub.

Source: Three Gorges Daily