The construction of Xiongan New Area is changing with each passing day, and the achievements of the construction are obvious to all. Here is known as "Asia's largest underground comprehensive transportation hub", with railways, subways, buses, terminals, and wharfs. This is the Beijing City Sub-Central Station. The reporter takes you into this huge project serving the coordinated development of Beijing, Tianjin and Hebei, and gives you an overview of the steel imprint on the magnificent picture scroll of the land of China!

The city's sub-central station comprehensive transportation hub is the largest underground comprehensive transportation hub project in Asia. After completion in 2024, citizens can go directly to Xiong'an New District in 1 hour, Capital International Airport in 15 minutes, and Daxing International Airport in 35 minutes. This may be an important reason why builders are on duty on holidays.

When they came to the foundation pit, the reporter saw Feng Quan at a glance. He is directing the builders to plan and mill the road. The fog cannon is also running at full power to reduce dust.

"How is the office arranged like that?" the reporter asked. Feng Quan replied: "The project is catching up with the major milestones, and the construction period is not waiting for anyone, so I really can't leave." But in his heart, Feng Quan still misses his family very much. On the eve of National Day, he bought massage chairs for his parents, clothes for his wife, and cakes for his daughter from the Internet. "Daughter-in-law told me, don't worry at home, let me take care of myself..." Feng Quan pursed his lips when he said this.

Quickly adjusting his mood, Feng Quan introduced the project clearly and logically. The West Side Road of the East Sixth Ring Road is a north-south traffic artery in the sub-center of the city. In order to make room for the construction of the comprehensive transportation hub project of the sub-center station, the road has been guided. However, the complex communication, tap water, sewage, reclaimed water and other pipelines around the original road surface must also be guided and modified, otherwise the new foundation pit cannot be excavated, and the construction sites on the east and west sides of the East Sixth Ring Road cannot be connected.

"This job is not easy, it has to be the same as embroidery." Feng Quan said, what is going on in front of him is a key step in the project: confirming the direction of the pipeline. Due to the many temporary constructions in the site, it is difficult to judge the direction of the pipeline, and it can only be confirmed by the builders planing and milling the road surface and digging pits. After the completion of the pipeline guide reconstruction, the builders will excavate another foundation pit with a depth of 8 meters and an area of 15,000 square meters. While digging 4,000 square meters of soil at full power every day, they had to cover it in time to reduce dust, and build a solid underground continuous wall to prevent the foundation pit from "making dumplings". The working position and the orientation of the boom of the heavy-duty crane should also be designed in advance, so as not to cause disturbance to the Beijing-Harbin Railway running on the north side of the construction site.

Feng Quan changed the subject and pointed to the west side, where builders were hoisting steel pipe columns in the foundation pit under construction. "When the excavation of the new foundation pit is completed in the middle and late this month, we will have to do this work." By then, the steel pipe column with a maximum weight of 80 tons will need to be hoisted by two cranes. The tilt range must be within 2 centimeters, which means that the vertical accuracy error cannot exceed one thousandth. During the hoisting process, the inclinometer and the total station are monitored in real time. Once the data is abnormal, the calibration will be started immediately to ensure that the vertical accuracy of the steel pipe column is 100% up to the standard.

Together with the new foundation pit covering an area of 15,000 square meters, the area of the foundation pit of the urban sub-central station comprehensive transportation hub project will reach 35,000 square meters.

How to prevent such a large foundation pit from collapsing? According to Feng Quan, since the project is an underground three-story structure, which belongs to an ultra-deep and super-large foundation pit, in order to ensure safety, the builders did not start construction from the deepest B3 floor, but reversed the construction process and first covered the top. slab construction, and then excavate the soil under the cover slab to build B2 and B3 floors.

Although this innovative construction method increases the difficulty of the project, it replaces the temporary internal support structure in the traditional foundation pit project with a formal main structure, which not only reduces the abandoned structure, but also improves the safety of project implementation. Editor/Xu Shengpeng