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Have you seen the thick, four-storey screw in the washbasin? A new high-speed railway in Ningxia is fixed on this screw.
On January 7, the Science and Technology Daily came to the construction site of Ningxia Yinwu Passenger Dedicated Line and found that the compacted foundation was covered with concrete discs the size of dining tables. These discs are nuts; below them are 20 meters long and 40 centimeters in diameter screws, buried in the soil. This kind of concrete screw is called "screw pile" by engineers.
"Screws are stronger than nails." Gou Shengluo, chief engineer of the project and municipal environmental protection company of the First Bureau of China Railway, said, "In the same way, threaded piles are more reliable than bare piles. Two-thirds of its lower part is threaded, closely occluding the soil.
This new technology has just been invented, and a small amount of it has been used in construction before, and the Yinwu high-speed railway project has been applied on a large scale. Over 120,000 roots were used in the whole line, and a series of construction methods were innovated by the First Bureau of China Railway.
The reason why the high-speed railway is not upside down is that the track is so flat that the roadbed cannot settle. The support of the Yinwu high-speed railway is a 15-20 meter long cement pile, which passes through the soft soil and is inserted into the harder stratum.
The big screw is made as follows: the drill rotates the screw into the ground and rotates out for a moment; the pipe at the top of the screw EWS out concrete and injects holes at the same time, and a cement screw is formed from bottom to top.
Threaded piles will compact the foundation soil and have greater friction with the foundation. When the screw pile replaces the bare pile, the pile density can be reduced by half and the material consumption can be greatly reduced.
"The key is to synchronize the drilling in and out. If the drilling goes down three times and reduces one pitch, the drilling goes up three times and raises one pitch, otherwise the newly drilled thread will be damaged." Gou quoted Lao as saying, "For this reason, the drilling rig current should be stable, and the distribution box should be precisely controlled by the computer." The new screwdriver is more than twice as expensive as the traditional rig.
At present, Tibet and Ningxia are the only provinces without high-speed rail in China. The Yinchuan-Wuzhong high-speed railway links two cities in Ningxia: Yinchuan and Wuzhong. It will open in August. It is also the first ballasted high-speed railway in China. Ballistic means that the track is laid on gravel. Previously, China's high-speed rail was laid on cement slabs. The Beijing-Zhangjiakou Railway under construction will be the second ballasted high-speed railway. Ballasted track is easy to adjust settlement and has lower maintenance cost.