China Bridge, China Road, China Tunnel, China Port, China Ship, China Car, China Building, China High-speed Railway, China Nuclear Bomb, China Aerospace ...... On the 75th anniversary of the founding of the People's Republic of China, countless great achievements have been made and countless great projects have been realized. China's science and technology have gone through a difficult and extraordinary 75 years with the growth of New China. Let us look back on the 75 years of glorious history of science and technology in our motherland!
Hangzhou Bay cross-sea railway bridge north channel bridge overhead renderings
As the world's longest sea-crossing high-speed railway bridge, the Hangzhou Bay Sea-crossing Railway Bridge is the middle channel bridge project, creating a new China and the world's best.
The Hangzhou Bay cross-sea railway bridge has a total length of 29.2 kilometers, including three channel bridges in the north, middle and south and approach bridges across the embankment, the sea and the shallow area, which is an ultra-long high-speed railway bridge cluster project. With a double-track ballastless track design with a speed of 350 kilometers per hour, it is currently the world's longest high-speed railway bridge with the highest construction standard. After completion, it will set a number of world records and be a milestone in the field of high-speed railway bridge construction in the world.
The Hangzhou Bay Cross-Sea Railway Bridge is a control project of the Nantong-Ningbo high-speed railway, which crosses the sea and is a double-track high-speed railway bridge with a design speed of 350 kilometers per hour. Construction of the bridge began in November 2022 and is expected to be completed by the end of 2027.
The total length of the waterway bridge in the Hangzhou Bay cross-sea railway bridge is 1430.8 meters, and the double main span of 448 meters is used to make a three-tower double-cable-surface steel truss cable-stayed bridge, with a total of 6 piers, and the first pile drilled in the waterway bridge on the same day is the No. 84 auxiliary pier No. 16 pile.
Hangzhou Bay is a typical "trumpet-shaped bay", which has the characteristics of large tidal range, strong erosion, rapid current velocity, deep silt layer and shallow gas, etc., which makes foundation construction difficult, high ecological and environmental protection requirements, and high operation safety risks. In order to ensure the smooth progress of the pile foundation drilling work of the China Waterway Bridge, the construction management unit has set up a scientific research team to tackle 8 topics such as offshore construction safety risk monitoring technology and large-scale ship platform avoidance technology.
It is understood that the Nantong to Ningbo high-speed railway is an important part of the mainland's "eight vertical and eight horizontal" high-speed rail network coastal passage, the new line is 301 kilometers long, the design speed is 350 kilometers per hour, and the construction period is 5 years. After the completion of the project, it will promote the improvement of the road network structure in the Yangtze River Delta region, greatly facilitate the travel of the people along the line, and is of great significance to promote the integrated development of the Yangtze River Delta.
The first bored pile of the South Channel Bridge was successfully poured——
At 21:30 on March 3, with the last concrete injected into the pile hole, the first bored pile of the South Channel Bridge of the Hangzhou Bay Cross-sea Railway Bridge was successfully poured, and the project construction entered the "fast lane".
Located in Qianwan New District, Ningbo, the South Channel Bridge of Hangzhou Bay Cross-sea Railway Bridge has a total length of 814.5 meters and adopts a steel truss combined beam cable-stayed bridge structure, with a main span of 364 meters. The construction is the No. 18 bored pile of pier 159 of the South Channel Bridge, with a pile diameter of 2.5 meters to 2.8 meters, a pile length of 122 meters, and a drilling depth of about 146.6 meters, using C40 underwater concrete, and the amount of concrete required for a single pile is 639.6 cubic meters.
"The structure of the reinforcement cage is unique, the inner and outer double layers of reinforcement are intertwined, the number of main reinforcements is large, the connection process is complex, and the production is extremely difficult. In addition, a total of 13 pipelines such as acoustic measurement pipes and grouting pipes are cleverly arranged in the cage, which undoubtedly further increases the difficulty and time-consuming docking of the reinforcement cage. Sun Jiawei, deputy head of the offshore section of the construction party CCCC Second Harbor Bureau, introduced. In order to further improve the construction efficiency, the team carried out the pre-assembly of the reinforcement cage on site in advance, and adopted an electric wrench with 7 joints to butt the reinforcement sleeve, which can save 40 minutes per joint, which greatly reduces the docking and lowering time of the reinforcement cage.
"The depth of the pile foundation hole is more than 145 meters, and the geology is mostly clay and silt, which has extremely high requirements for the performance of the mud in the hole. Sun Jiawei said. In the face of this problem, the main pier team conducted many in-depth scheme discussions and mud ratio tests. After repeated comparison and screening, high-quality bentonite, CMC and other pulping materials were finally selected. During the construction of bored piles, the team also innovatively adopted the combined process of "rotary drilling overburden pilot hole + reverse circulation drilling rig hole formation" to ensure the verticality of the borehole. The adoption of a series of measures and a large amount of preparatory work in the early stage ensure that the entire pouring process is "foolproof". (Xinhuanet, Chinanews.com, Zhejiang Government Service Network)