On Chaowai Street, the bustling "third commercial street" of the capital, vehicles and pedestrians shuttle back and forth, and citizens and tourists rub shoulders one after another. And beneath the ground, a huge building complex, the future "business card" of Chaoyang District, is quietly taking shape.
On February 14, the fifth day of the Lunar New Year, the construction site of Dongdaqiao Station of Beijing Rail Transit Line 28 of China Railway 16th Bureau on Chaowai Street was already a lively and busy scene. The large-scale groove machine is excavating the earthwork from a depth of more than 70 meters underground, and more than 20 construction personnel are nervously and orderly carrying out steel bar cutting, binding, welding and other processes. As the deputy production manager of the project, Ma Jianjian has been staying at the site since 10 o'clock last night, always paying attention to the construction progress of the first underground diaphragm wall of Dongdaqiao Station in the new year.
Construction crews carry rebar.
In general, in the construction of subway stations, the depth of the underground diaphragm wall is 30 to 40 meters. Dongdaqiao Station is currently the deepest subway station in Beijing, and the enclosure structure adopts the ultra-deep ground wall of 81 meters in the standard section and 83 meters in the shield section, which is the first case in the history of Beijing subway construction, and the construction link is complex and extremely difficult. Ma Jianli said that due to the tight construction period of the project, he took the initiative to ask for help in Shandong, and took the lead in returning to work on the third day of the Lunar New Year, a day of visiting relatives and friends, and raced against time to promote the progress of the project with all the builders.
Binding of rebar on site.
Dongdaqiao is adjacent to the Workers' Stadium and Sanlitun Embassy District in the north, and the International Trade Center CBD business district in the south. Dongdaqiao Station of Beijing Rail Transit Line 28 under construction is the first five-storey double-column three-span island subway station in Beijing, with a length of 210 meters, a standard section width of 28 meters, and a total construction area of about 7960,000 square meters, the maximum buried depth of the floor is 468 meters, the maximum lifting weight of the steel cage is 110 tons, which is the deepest underground diaphragm wall rail transit project in China. In the future, the station will form a four-line interchange with Metro Lines 6, 17 and 22, becoming one of the most important hubs of Beijing's subway network.
Renderings of the four-line transfer at Dongdaqiao Station.
In the face of such a large volume and difficult underground engineering construction in a bustling commercial district, Ma Jianjian, who has been engaged in subway construction for 20 years, also believes that it is a big challenge. In order to ensure the safety, quality and progress of the project, the ultra-deep ground wall must be constructed 24 hours a day, and the steel cage hoisting must be carried out at night.
Night reinforcement cage hoisting.
We are responsible for the absolute safety of the subway construction. The geological conditions of Dongdaqiao Station are complex, silty sand, silty clay and pebbles appear alternately, and the groove forming machine is easy to produce the phenomenon of 'paste wheel' in the clay layer, which prolongs the groove forming cycle, and then leads to the instability of the groove wall of the ground wall. Ma Jianjian introduced that in order to solve the problem of difficult control of ultra-deep and ultra-thick wall groove accuracy, the project team made great efforts in equipment selection and process optimization, and adopted the domestic advanced double-wheel milling groove machine and rotary drilling rig combined construction, which greatly improved the work efficiency and effectively reduced the noise and ensured the normal life of the surrounding citizens.
On-site equipment combination construction.
Zhang Yanlei, the chief engineer of the project, also from Shandong, chose to be on duty at the construction site this Spring Festival. "From the 29th day of the Lunar New Year to the 3rd day of the first lunar month, we let the workers go home to rest and have a good New Year. The project technical team took advantage of the past few days to carry out detailed planning on the construction organization and traffic guidance plan, and strive to successfully complete the first phase of the construction wall construction in 2024, and carry out the next step in advance to win time for the subsequent excavation of the main body of the station. ”
The on-site management personnel inspect the construction of the ground connecting wall.
The limited construction site is another problem faced by the construction of Dongdaqiao Station. "In the construction stage of the underground diaphragm wall, the area will be carried out in 3 times. At present, the first phase of the construction site is transformed from the original Chaowai Street, and after the construction of 63 diaphragm walls in this area is completed, a cover plate will be erected above and road traffic will be restored, so as to free up the space of the second phase of the site, and then implement the construction of the remaining 65 diaphragm walls. Zhang Yanlei introduced that the extreme compression of the construction space is to reduce the impact on the ground road traffic as much as possible, and the project team scientifically divides the construction area to achieve the efficient connection of various processes in a very limited site.
The construction crew welds the rebar.
When it comes to the future construction plan of Dongdaqiao Station, Zhang Yanlei's calm expression reveals pride. "In order to solve the stubborn problems of complex surface roads and traffic congestion of Dongdaqiao, Beijing has built Dongdaqiao Station into the city's first rail transit micro-center based on the integrated and sustainable development and utilization of urban underground space. In the future, the underground space of the triangle plot of Dongdaqiao will realize the four-line transfer of three-dimensional rail transit, while the shallow underground space can also be compatible with the function of pedestrian crossing, and the ground will be built into an urban green park and regional landscape center to maximize the intensive and efficient use of aboveground and underground space. ”
Renderings of the completion of the station.
At present, Dongdaqiao Station is speeding up the construction of the first phase of the ground connecting wall. After the completion of Beijing Metro Line 28, most of the main office areas, urban residential areas and key functional areas in the CBD area will be connected in series, further opening up regional connections, encrypting the transportation network, optimizing the supply of urban rail transit, and promoting the intensive, efficient and integrated development of rail transit and urban space. (China Railway 16th Bureau).