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There is a saying that there is no way in the world, but it’s hard for anyone to come
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Even if you are “infrastructure maniac”, look at the picture and answer: how do you need to go from the beginning to the end in the figure below? Between two points, the line segment is the shortest, but the path in the picture tells us that the problem is not so simple
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This is Tongjing Road north extension, which has plagued Suzhou people for 10 years
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In order to bypass this section of the road, drivers have to make a big circle, close to 10 kilometers, to catch up with the traffic jam
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It’s really “dark sky”
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There is no hour to pass, but it’s impossible! Why？ In 2021, how can there be a “dead end” for the “infrastructure maniac”? There are thousands of dead end roads in the world, each of which has its own reason
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Suzhou is a cultural ancient city with developed water system, modern and classical urban planning, and complex transportation facilities
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With the development of the city, there are more and more lines, which is a “dead end” here
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Tongjing road in Suzhou is called “super dead end road” by the local people, and the two kilometer road has not been repaired for more than ten years It’s a world-class problem
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But in fact, as early as 13 years ago, the Tongjing road project was put on the agenda, but the road construction plan has been delayed
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The schematic diagram of Tongjing Road, within a short span of 400 meters, has gathered several mountains of ancient buildings, rivers and existing operating lines
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This road is only two kilometers long, and it goes through Shantang historical and Cultural District, a national AAAA scenic spot
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In the block, in order not to damage the landscape, the viaduct can not be used
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Even through these difficulties, it is necessary to seamlessly link up the major risk points in operation, such as (3) Shanghai Nanjing intercity high-speed railway, (4) Beijing Shanghai railway, and (5) North Ring Expressway
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The super dead end road is not a false name
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Those who have worked in projects all know that it is “S-level” difficulty to carry out any of the above items, not to mention focusing on the short length of more than 400 meters
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In particular, the Shanghai Nanjing intercity railway is a high-speed railway with a speed of 350 km / h, which can not be shut down, and can not tolerate any disturbance or any accident
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Respecting history and developing the city at the same time, it is imperative to get through Tongjing road
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In a flash, the infrastructure maniac of more than 10 years has finally accumulated a big move
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They want to use domestic shield machine to get through this dead end road from underground at one stroke
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CCTV finance and economics “half an hour” column video October 26, 2020, the domestic “Gusu” large diameter shield machine jointly developed by China Railway Construction 14th Bureau and China railway construction heavy industry Co., Ltd The cutter head of the machine turns slowly, and the broken road that has been shelved for more than ten years begins the journey of crossing
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The “Gusu” shield machine on Tongjing road starts
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Although there is no movement on the ground, underground, they are completing the “most difficult case” of large shield passing through the operating high-speed railway in the history of world construction
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Gusu shield machine is a huge object with the largest excavation diameter of 13.67 meters
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The shallowest distance above it is only 6.47 meters from the ground
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In the engineering field, if the shield machine wants to move forward under this buried depth, it is equivalent to carving on the egg film that can be broken by blowing bombs
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Moreover, if the Shantang River above the tunnel is not careful, water gushing, breakdown, collapse and other accidents will follow, and every one of them will be a disaster
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Wu Juncai, the shield driver of China Railway 14th Bureau, who controls the cutterhead tunneling, describes his work as “walking on thin ice”
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Through the ancient buildings and Shantang River, the Shanghai Nanjing intercity railway and the Beijing Shanghai railway are the most important to get through the tunnel, and the difficulty can be said to be in the “atmosphere”
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The design speed of 350 km / h Shanghai Nanjing intercity will gallop from the top of the tunnel every 3 minutes
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For more than 10 years, the construction scheme of the dead end road has been rejected again and again, mainly because once the settlement exceeds the standard in construction, it will bring serious safety impact on the high-speed railway operation
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Therefore, the horizontal and vertical displacement in the construction process must be controlled within 2mm
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Chen Qifa, chief engineer of China Railway Construction Fifth Research Institute, made great efforts for the 2mm
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As a result, the spirit of infrastructure maniac is fully demonstrated when solving engineering problems
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If we say that we used to build what kind of equipment and what we did, we will build what kind of equipment we have now! After so many years of experience, we have the technical reserves to complete some seemingly impossible tasks
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Relying on the maturity of experience, equipment and technology, it has gradually become a reality
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There is no precedent in China or even in the world for large diameter shield machine to cross the running high-speed railway
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They have to find a “super guard” for the high-speed railway to protect driving safety
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In order to avoid the running high-speed railway from being disturbed by the advance of the shield machine, 72 pile foundations should be used underground to form “four walls” at the bottom of the high-speed railway bridge without excavation, so as to firmly protect the main body of the bridge
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At the same time, the shield machine should accurately cross the invisible target from the underground
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However, after comparison, the imported equipment needs more than 10 million yuan, which may not be suitable for the site conditions
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In particular, the site working face is very narrow, and the clearance from the high-speed railway is only 2.5 meters, so the large equipment is useless
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After more than one year’s test, the No.5 railway research and Development Institute developed a low clearance pile driver, which divided the whole into parts, drove the pile by relay, and the reinforcement scheme of Underpass high-speed railway was approved
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Low clearance isolation piles make it possible for large shield machines to cross and operate high-speed railway, and also fill a gap in tunnel construction technology in the world
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At the beginning of 2021, the shield machine smoothly passed through the Shanghai Nanjing intercity railway and Beijing Shanghai railway to open the dead end road
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The two key technical difficulties were successfully overcome
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The world’s “most difficult case” which has been in Suzhou City for more than ten years will be completed and opened to traffic in 2022
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From theory to practice, from drawings to landing, this is not just a paper talk
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Throughout the world’s urban construction planning, the end of the road is always an unavoidable pain
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But Chinese engineers have been sharpening their swords for ten years, turning the impossible into the possible and turning the dead end road into a thoroughfare
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We not only have “Chinese speed”, but also “Chinese patience” and “Chinese persistence”; we not only have the great power of scientific and technological innovation of central enterprises, but also have the original mission of creating a better life for the people! Source: state owned Xiaoxin
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