Edited by: Du Yu
According to CCTV Finance and Economics on December 20, the shield machine is known as the "king of construction machinery", which can cross mountains and mountains, rivers and seas, and is an important symbol to measure the level of a country's manufacturing industry. For a wide variety of underground projects, the shield machine is an indispensable tunneling tool. Today, 7 out of every 10 EPBs in the world come from China.
52 shield machines were constructed at the same time and the underground "aircraft carrier" group was operating
In 2022, 52 domestic shield machines built by China Railway Construction Heavy Industry Co., Ltd. will form a shield construction machine group to participate in the tunnel construction of Guangzhou Metro Line 18 and Line 22. There are many urban buildings on the ground, the underground municipal pipe network is criss-crossed, and the complex geological conditions severely test the performance of the shield machine.
Image source: CCTV Finance
Guangzhou, especially in the Pearl River Delta region, has soft rock, hard rock, and even soft and hard alternately. For this purpose, the R&D personnel developed a refrigerated cutterhead, which freezes the soil layer into a shell-type safety body, and then excavates the rock formation.
Image source: CCTV Finance
The diameter of the "Hero" slurry balance shield machine is 14.8 meters, which is the largest diameter shield machine in the high-speed rail tunnel in China.
Image source: CCTV Finance
Tianxiang Avenue Tunnel is one of the most complex high-speed rail shield tunnels in China with the most complex construction environment and geological conditions, and the cutterhead cutter is facing the problem of high wear and the dilemma of cutterhead mud cake.
Image source: CCTV Finance
For this purpose, the R&D team has specially equipped an intelligent perception system for the cutterhead tool status, which can monitor the cutterhead temperature and tool wear status in real time and display it in the main control room to assess the risk of cutterhead mud cake in advance.
China Railway 14th Bureau: Build a first-class brand and empower transformation and development
According to Xinhuanet, on December 16, the super-large diameter shield machine "Yuanmeng" developed by China Railway 14th Bureau was successfully rolled off the assembly line in Changsha and will be used in the construction of the Suzhou East Tunnel of the new Nantong-Ningbo high-speed railway.
At the same time, the shield machine is equipped with a complete set of advanced technology of "push-spelling synchronization + synchronous double-liquid grouting + integral fully prefabricated box culvert synchronous assembly", which is the first application in the domestic super-large diameter shield equipment, which will comprehensively improve the safety, efficiency and quality of shield construction, and add another weapon to the "China Railway 14th Bureau Shield Brand".
Image source: Xinhuanet
The shield machine of the Hebei section of the first cross-provincial urban rail in Beijing and Hebei was launched
According to the central radio network, on December 15, the sixth shield machine of the Hebei section of Beijing Rail Transit Line 22 (Pinggu Line) undertaken by the consortium of CCCC First Public Bureau Group Co., Ltd. and CCCC Tunnel Engineering Bureau Co., Ltd. was successfully launched at the north end of Chaobai Street Station in Yanjiao Town, Sanhe City, Hebei Province. As the last shield machine invested in the project, this launch marks that the project has fully entered the shield construction state.
Line 22 (Pinggu Line) is the first inter-provincial urban rail transit line in Beijing and Hebei, and it is a landmark line to build a high-quality "Beijing-Tianjin-Hebei on the track". The project starts from Dongdaqiao in Chaoyang District, Beijing in the west, and ends in Pinggu New Town, Beijing, passing through Chaoyang District, Tongzhou District, Sanhe City, Pinggu District and other areas in Hebei Province, connecting key functional areas such as Beijing's Central Business District, urban sub-center, Yanjiao, Pinggu New Town, etc., with a total length of about 81.2 kilometers.
The Hebei section of the project undertaken by the consortium of CCCC First Public Bureau Group Co., Ltd. and CCCC Tunnel Engineering Bureau Co., Ltd. is about 30 kilometers long, with a total of 5 stations and 6 sections. The "Endeavour" with a diameter of 8.29 meters, an overall length of 109 meters and a total weight of more than 1,400 tons is a domestic large-diameter shield machine, which will be excavated in the same direction as the right line "with the same number" (the fourth) shield machine, and jointly complete the excavation task of the 5039-meter shield section of the double line of Chaobai Street Station - Gaolou Station.
The cutterhead is the largest in the world, and the main bearing is the largest in the world
According to CCTV Finance and Economics, according to different construction conditions, the cutterhead cutter, operating system, hydraulic system, etc. are transformed according to local conditions, which is already commonplace for China Railway Construction Heavy Industry, which has firmly grasped the core technology. For 20 years, it has been relying on imported cutterheads, not only to achieve localization, but also to maximize the size of the cutterheads.
In the past, the main bearing, as a key component of the cutterhead drive system, has been monopolized by foreign countries, not only the price is up to tens of millions of yuan, but also technology, production and service are often controlled by others. In 2018, the state released a list of key technologies "stuck neck", and China Railway Construction Heavy Industry Co., Ltd. launched the technical research of the main bearing of the domestic large-diameter shield machine from backward to surpassed.
Until October 12, 2023, the main bearing of the world's largest diameter and heaviest monomer integral shield machine rolled off the assembly line in Changsha, which marks that the development and industrialization capacity of domestic super-large diameter main bearings ranks among the world's leading level.
Image source: CCTV Finance
In addition to the main bearing, the localization of several key components has created an extraordinary domestic shield machine. The "Yongning", which can climb slopes, is the first large-diameter and large-inclination inclined shaft tunnel shield machine in China, and has always maintained an upward climbing attitude when operating in the tunnel.
In addition to the motor, there is also a reducer. The motor on the EPB rotates extremely fast, at more than 2,000 revolutions per minute, but the cutterhead of the EPB rotates "slowly enough", as low as 1.5 revolutions per minute. The huge speed difference must be achieved by relying on the reducer. In order to overcome this technical problem and realize the localization of the reducer, China Railway Equipment has joined hands with the Zhengzhou Machinery Research Institute of the China Academy of Mechanical Sciences to jointly carry out research and development.
Now, some of the reducers they have developed can continue to excavate for more than 10,000 hours without failure under extreme conditions, filling the gap in the application of such domestic reducers.
Image source: CCTV Finance
In recent years, focusing on the shortcomings of the shield machine industry chain, China Railway Equipment has contacted advantageous universities and institutes, upstream and downstream enterprises in the industry, and gradually increased the localization rate of the whole machine parts to more than 90%, forming 22 international leading technologies. At present, China Railway Equipment has established cooperation with more than 1,000 upstream and downstream enterprises in the industrial chain.
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