Recently, construction on multiple transportation projects in Jiangsu is in full swing, with builders at various project departments working hard, presenting a bustling scene of vigorous activity.
Recently, after 70 consecutive hours of construction, the south anchorage of the north channel bridge of the Zhangjinggao Yangtze River Bridge completed the first-layer pouring of its base slab, and the south anchorage of the north channel bridge entered the mass concrete construction stage.
The anchorage is a key load-bearing component of the bridge, playing an important role in anchoring the entire bridge. The south anchorage foundation of the north channel bridge of the Zhangjinggao Yangtze River Bridge adopts a composite anchorage foundation structure of a circular diaphragm wall with an outer diameter of 90 meters and a wall thickness of 1.5 meters, combined with deep foundation reinforcement and a horizontal sealing base. The anchorage base slab is poured in 3 layers, with thicknesses of 2 meters, 2.5 meters, and 2.5 meters respectively. The first layer of the base slab poured this time is 2 meters thick, with a cumulative concrete pour of 10,900 cubic meters. The completion of the first-layer pouring of the anchorage has initially formed a closed reinforced concrete integral structure, which will effectively reduce the construction risks of foundation pit inrush and base slab uplift caused by the rising Yangtze River water level during the flood season, ensure the structural safety of the deep foundation pit, and lay a solid foundation for safely and efficiently advancing the project construction.
During the construction process, in response to difficulties such as weak geological foundations and the high risk of cracking in mass concrete, the project construction team adhered to innovation-driven development and independently developed devices such as high-precision detection and efficient removal of sediment in ultra-deep diaphragm walls, effectively ensuring the construction quality of the diaphragm walls; adopted an intelligent ultra-high-pressure jet grouting pile construction process to insert and drive 2,497 jet grouting piles into mud as soft as "tofu," greatly improving the bearing capacity of the foundation; jointly carried out research with scientific research institutions on temperature control and crack prevention technologies for mass concrete to reduce the risk of cracking and eliminate harmful cracks; and built 6 major digital management systems, including an intelligent construction system for diaphragm walls, a digital twin system for deep foundation reinforcement, and an intelligent temperature control system for mass concrete, achieving intelligent analysis, early warning, and control throughout the entire construction cycle.
　　North Approach Bridge of Longtan Yangtze River Bridge: All bridge deck slab installation completed
Recently, as the last variable cross-section bridge deck slab was accurately placed on the steel girder of the second span of the north approach bridge of the Longtan Yangtze River Bridge, the installation of 1,336 bridge deck slabs for the north approach bridge was successfully completed. At this point, the main structure construction of the north approach bridge has been fully completed.
The north approach bridge of the Longtan Yangtze River Bridge has a total length of 1,330 meters. Its superstructure adopts a steel-concrete composite girder form, with trough-shaped steel girders at the bottom and precast concrete bridge deck slabs laid on top. The steel girders and bridge deck slabs are connected through shear studs and wet joints.
The lifting construction site for the bridge deck slabs of the north approach bridge has a complex environment, involving numerous underground pipelines and cross-operation with the main cable and catwalk works, making construction highly difficult. To complete the bridge deck slab installation task of the north approach bridge with guaranteed quality and quantity, the project construction team planned ahead and made careful deployments, held multiple safety and technical discussion and exchange meetings, and conducted a comprehensive analysis of the construction process, technology, safety, and standards, with briefings at every level. During construction, 1 350-ton crawler crane and 1 320-ton crawler crane were equipped for bridge deck slab installation, and 9 flatbed trucks were used for bridge deck slab transportation. Among them, a single bridge deck slab has a maximum length of 7.85 meters, a maximum width of 5.5 meters, and a maximum weight of approximately 31.8 tons. Since the successful installation of the first bridge deck slab in November 2023, after 203 days and nights of hard work, the bridge deck slab installation of the north approach bridge was completed safely and efficiently.
In the next stage, the north approach bridge of the Longtan Yangtze River Bridge will focus on the construction of wet joints and crash barriers, sprinting toward the goal of completing the bridge within the year.
　　Jiangbei Working Shaft of Haitai Yangtze River Tunnel Completes Base Sealing
Recently, after more than 30 hours of continuous construction, the final concrete pour for the Jiangbei open-cut section of the Haitai Yangtze River Tunnel was completed, and the launching working shaft successfully completed base slab sealing before the flood season, marking the transition of the Jiangbei open-cut section from foundation pit excavation to main structure construction and providing a strong guarantee for the subsequent lifting and lowering of the shield machine into the shaft.
The working shaft foundation pit sealed this time is 25 meters long, 53 meters wide, and 31.896 meters deep. It adopts the open-cut sequential construction method, with an excavation earthwork volume of 50,000 cubic meters and a pouring area of 1,568 square meters.
The foundation pit has extremely abundant groundwater and features deep excavation and large scale. To ensure the stability of the foundation pit and control surface settlement, the project construction team organized multiple special discussion meetings on the construction plan and deployed monitoring and key construction tasks at each stage according to on-site progress. During construction, refined management was strengthened, material acceptance was strictly controlled, and personnel were assigned to monitor the working face 24 hours a day by area. Through systems such as automated foundation pit monitoring, steel support servo control, and intelligent access control, as well as a smart safety risk control platform, real-time remote monitoring of on-site personnel, machinery, and materials was achieved. During pouring, embedded sensors were used to monitor concrete temperature in real time, technical specifications were strictly followed, and vibration was monitored point by point to ensure dense concrete vibration and guarantee pouring quality.