Original title: 7 out of every 10 shield machines in the world come from China!The domestic "underground aircraft carrier" is in the forefront of the world.
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 TBMs were working at the same time
Underground "aircraft carrier" group operations
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.
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.
The diameter of the "Hero" slurry balance shield machine that is being excavated in the Tianxiang Avenue tunnel of the Changjiu high-speed railway has reached 148 meters, it is the largest diameter shield machine for high-speed rail tunnels in China.
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.
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.
20 years from scratch, from weak to strong,The cutterhead is the largest in the world
The main bearing is the largest in the world
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 mastered 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 highest tens of millions of yuan, 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.
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.
The main drive motor of Yongning is 8 sets of domestic 350 kilowatt motors. The listing of domestic motors has reduced the procurement cost by about 5% compared with imports, and greatly saved the equipment delivery cycle.
In addition to the motor, there is also a reducer. The motor on the shield machine rotates extremely fast, more than 2,000 revolutions per minute, but in contrast, the cutterhead of the shield machine rotates "slowly enough", as low as 15 turns. 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.
Compared with imported similar reducers, the work efficiency of some reducers has been increased by nearly 25%, and the technology has reached the international leading level, while the cost has been reduced by nearly half.
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.
*: CCTV Finance].