In line start building more than seven months later, Lanzhou Metro Line 1 of a project to usher in an important node, November 1, between the beach to Ma Ying-door begins shield tunnel under Yellow River floodplain departure, expected later in the year , the Yellow River Bridge on the west side of the river at Silver Beach, two over 400 meters long underground tunnel will run through the Yellow River. This will be the first time in domestic transportation projects across the Yellow shield construction, high construction difficulty, called domestic initiative.
"Yellow River Crossing Tunnel 100 meters before the operation by our excavation, the project to learn from, after 100 meters operated by the project department technicians, we provide technical guidance in the field."
November 1, at a time on Saturday, on the occasion of the sky at dawn, the slightest rain and snow falling sky. Towards the door in a peaceful area of rail transit projects beaches ministry, hundreds of workers had gathered at the site, rubbing his hands in the cold, nervous and excited to look forward to the arrival of an important moment.
8:08, fireworks, gun salute sound pierce the morning quiet, Lanzhou Metro Line 1 project Ying-door Beach station to wear down the Yellow Shield Matan station originating ceremony.
Subsequently, people flocked to the gantry next to the metro station "patio" mouth overlooks Phi Hung wounded beneath the "Golden City on the 5th" shield machine, buzzing with the "big guys" will be how to work.
Dozens interim order along the escalator into the station ground floor, the face is stopped at the station on the west side of the tracks in "Golden City on the 5th" shield machine, the nearly one hundred meters long "big guy", the head arrived at the tunnel entrance Department, was a huge steel rack fixed up. Dozens of staff manufacturers, project department and supervision around the shield machine busy. Wearing orange overalls shield machine manufacturers and technical personnel, the cat got into each end of the fuselage body shield machine, the checking line, ancillary equipment and power control, for final preparations for the departure of shield.
In the shield machine head, which is behind the shield of the host, forty-five technicians are assembled tunnel segments, which weighs 3.2 tons of arc-shaped concrete gantry crane into the shield is the rear of a small car, and then sent to a nearby car steadily along the tunnel boring machine hosts narrow track, hanging bridge connecting the hook followed by a large segment lifted, placed behind the rear slid onto the host machine can be rotated. Technicians segment with a huge nut fixed, rotating machines up, and then fixed the next piece tube sheet, pipe sizes 6 piece all fixed after the formation of a closed ring.
"Each loop has a 35 cm thick slices, 1.2 meters wide, before drilling the tunnel boring machine open, first assembled outside the tunnel 8 ring segments." Deputy General Manager of China Railway 16th Bureau Project Department Command at the scene said Stratum , outside the tunnel shield machine segment is to provide a friction thrust host assembled, "originating segment a total of 100 ring, which is 120 meters, 100 tablets can provide enough resistance to promote the hosts ahead and then fixed hosts outside the tunnel steel brackets can dismantled. "
A skill Shield manufacturer China Railway Construction Heavy Industry, told reporters, in order to allow the smooth conduct of shield tunneling, before digging 200 meters factory technical staff will provide help at the scene, "the former 100 meters from the Yellow River Crossing Tunnel Boring our operations, project department learning from the project after 100 meters operated by the Department of technicians, we provide guidance on the scene, the Ministry of operation after the project is fully skilled, and our work is done. "
"Ma Ying-door beach to beach area between Lanzhou, but also the first time through the subway tunnel shield construction of the Yellow River."
It is understood that since March 28 this year to start building across the board, Lanzhou Metro Line 1, the majority of the work area of a project pipeline Qiangai been launched, and the structure of the temporary road construction to ease the main station building envelope piles. As good construction conditions, the construction Matan Station, Olympic Station rapid progress, coupled with the test section two stations (Ying-door Beach station, Century Avenue Station) had already completed a range, so to Ma Ying-room door Beach Floodplain be the first to start the tunnel shield tunneling.
"Ma Ying-door beach to beach area between Lanzhou, but also the first time through the subway tunnel shield construction of the Yellow River." Lanzhou Metro Line No. 1 overall responsible for Yellow River Crossing Tunnel Design, China Railway First Survey and Design Institute of tunnel engineer Wang Fei said.
Wang Fei told reporters, Lanzhou Metro Line 1 in two of three beaches through the Yellow River region, located upstream of the Yellow River Yellow River Crossing range from geological conditions, the bottom of the Yellow River water permeability, high content of the sand and gravel, but also through the large building structures (Silver Yellow River Bridge). "The situation with Nanjing, Wuhan and other cities subway construction process through the river compared to the river, Ma Ying Yellow River Crossing project examples for reference interval no multiple constraints brought together, with the typical characteristics of Lanzhou, high construction difficulty, called national initiative . "
Stratum, from the preliminary geological exploration results, Ma Ying-range segment through Yellow River Sand and Gravel content up to 78%, as well as some up to 55 cm or more in diameter boulders, tunneling is extremely difficult.
In order to cope with difficult construction conditions, the construction side of Lanzhou Railway Co, Fang Railway First Survey and Design Institute of Design, Construction prescription Railway 16 Bureau Group After much discussion, the final choice of using advanced pressurized mud balance shield to bear crossing the Yellow River tunnel construction.
According to the China Railway Construction Heavy technical staff analysis, through Yellow River section of the complex geological conditions, if the ordinary EPB shield, due to lack of tunnel face pressure, the construction process of local soil instability or Bay Sand gushing problem will worsen . Meanwhile, in addition to water seepage even polishing is high, the content of large pebbles factors, since the formation positions in a special operation, the soil may collapse, resulting in damage to workers toxic gas, and therefore less likely to artificial excavation.
Stratum told reporters, Ma Ying Yellow River Crossing Interval uses the world's most advanced slurry shield machine, 6.48 meters in diameter, 96 m long, with a total weight of over 500 tons.
"When the earth pressure balance shield ordinary job, you need to muck Sinotrans and other ancillary operations, compared with mud pressure balance shield when the job is a closed loop." General Manager of Lanzhou Railway Co Assistant Sun Hongbin told reporters that the so-called mud pressure balance shield, "In fact, the principle is very simple, that is the whole shield machine via two inlet and outlet pipes and mud slurry separation system is connected to the job by the configured into the pulp slurry tube into the mud shield, shield the host of cutting under the sand and gravel in the mud washed through the tube into the mud slurry separation system, a large gravel after treatment was isolated as a spoil Sinotrans treatment, and mud then re-enter the tunnel boring machine, so cyclical. "
"Today, Maryland public can look forward to this time next year at the latest, four subway tunnel crossing the Yellow River all through millions of subway dream will be one step closer."
According to Wang Fei introduction, because of the great difficulty of construction, iron and a hospital in accepting the 1st line design beginning, commence construction of the Yellow River Tunnel Shield targeted research. "Before the specific design, we have done a lot of research work, referring YRCC flood approved evaluation reports, comparison of various construction program, just line location choice, tunnel depth, on the Yellow River Conservancy Commission will examine two years. "
After two years of study design, Ying Ma interval tunnel for the final selection of approximately 50 meters upstream of the Yellow River Bridge at Silver Beach, tunnels 22 meters away from the Yellow River embankment, the whole Ma Ying-right line length of 1906 m interval, the left line length 1908 meters, the next line through Yellow River reach length is about 404 meters.
It is understood that, in addition to the beach to Ma Ying-door room outside the floodplain, Lanzhou Metro Line 1 project in the Olympic range to the Century Avenue will cross the Yellow River, Yellow River Crossing section of tunnel length of this interval is 317 meters, despite the distance compared short, but also facing gushing, Chung sand, water leakage inside the tunnel, floating tunnel and other construction problems, but the Austrian World interval through Yellow River also have to go through a much larger segment than Silver Yellow River Bridge was built structures - deep Yellow River Bridge.
High Zhihong China Railway First Survey and Design Institute, Lanzhou metro project manager, said, wearing the Yellow River tunnel project under the 1st line, regardless of the design, construction or engineering organizations are having a very difficult challenge, but it also has a very unique innovation resistance, the construction of similar projects in the future is an important reference and guidance.
Sun Hongbin told reporters, Ma Ying intervals in order to ensure safe construction zone Austrian World Yellow River Crossing Tunnel Rail company through open tender, selected China Railway 16 Bureau and the China Railway 14th Bureau both have a wealth of experience through the river the river construction companies .
It is understood that Ma Ying-range left tunnel shield machine construction has been completed, according to the special construction program across the Yellow River, Ma Ying-range right lane tunnel origination is complete, ie after driving 120 meters, the left tunnel will begin originating Shield . Is expected next year from January to March, the right lane tunnel will be heading to the Yellow River, Yellow River and here comes the dry season, is the best season of shield construction. "According to the construction plan, Ma Ying-lane tunnels through Yellow River zone will be completed within 12 months, and if successful, we hope to complete within six months."
In addition, the reporter learned from the city rail company, Olympic Boulevard to Century Yellow River Crossing Tunnel use the same range of slurry shield, the current construction of the shield machine has been basically completed, will soon be transported to Lanzhou. "Today, Maryland public can look forward to this time next year at the latest, four subway tunnel crossing the Yellow River all through millions of subway dream will be one step closer." Rail company a responsible person confidently told reporters .
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