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Metro Construction Technical and Economic Analysis of Shield


[Abstract] Shanghai Rail Transit Yangpu Line of Ⅶ standard, for example, introduced the subway tunnel construction methods, processes and cost analysis.
[Key words] shield construction; Metro; construction method; cost analysis shield tunnel excavation is under the ground construction of tunnel construction methods, the use of shield as the excavation of underground soil and the soil supporting the tunnel lining and assembled machinery, driving a ring, a ring assembly, cycle work,abercrombie marseille, until the completion of the entire tunnel. In the subway tunnel in Shanghai, from 1989 in Metro One line works of construction of shield tunnel using since 2003, the Shanghai Rail Transit Yangpu Line (M8 line) for the first time using new technologies DOT shield tunnel , tunneling tunnel 2.6km. Shanghai has the world all the advanced equipment, and mastered the operation of its construction methods and techniques, the length of the tunnel construction, speed, quality, research and theory are close to the world advanced level. However, with foreign or not a small gap exists, from the construction point of view, the performance gap between Chinese and foreign technology in the Shield: The shield of foreign engineering methods and the whole variety,abercrombie paris, more single home construction method; section diversified, high-speed construction , neighboring construction, long distance, cost control has become the mainstream of foreign Shield technology; country in recent years, large section, large depth of neighboring construction technology matures, with little difference between foreign countries; country in the complex section, the cost is relatively backward control . 1 shield construction of the basic conditions shield construction of the basic conditions are: - to permit the construction of alignment holes for the shield and the ballast into and out of Liu's work well; - Tunnel should have sufficient depth, casing depth should be not less than 1 times the diameter of the tunnel; - relatively homogeneous geological conditions; - if you have enough single-hole spacing, hole with the hole and the hole with the other building (structure) of the clip between the soil (rock) body reinforcement for the horizontal direction, the minimum thickness 1.0m, vertical 1.5m; ⑤ from an economic perspective, when the small size of the project , construction cost is relatively high, such as a tunnel for less than 750m, with statistics, is considered to be not economical. Therefore, heavy traffic on the ground, ground buildings and underground pipelines clouds on the city demanding land subsidence, not by open-cut method, and groundwater development,ralph lauren pas cher, poor stability of surrounding rock , or the duration of the tunnel is long and requires urgent and can not use more economical mining method, the use of shield construction is economical and reasonable. Shield construction with the construction speed, the hole is relatively stable body weight, less impact on the surrounding buildings and other characteristics, suitable for soft ground construction. Is mostly in Shanghai soft ground, and taking into account the ground buildings, facilities, intensive,ralph lauren pas cher, a number of underground pipelines, higher factors of environmental protection requirements, the use of shield construction is more reasonable economy. 2 steps to shield construction shield construction and construction processes more complex high precision and technical content, the main construction steps are: - The Shield the beginning of tunnel construction by agencies and end of the construction of a working well, are well known and get to the departure (or assembly room, demolition of room); - Shield assembly at the end of the first wells in place; - hole formation reinforcement; - rely on shield jack thrust (the role has been assembled in good and working well, after lining the wall of ring) will shield the wall from the starting job openings at the launch of the well (this process for the shield out of its hole); - ; shield design in formation along the axis of advance, in advance while constantly unearthed and installed Lining; - the gap in time to grouting behind the lining to prevent the formation of mobile and fixed liner ring position; - Shield into the terminal working well and was removed (this process is shield hole), such as construction necessary, through the work station and then had a well or shield forward. Shield can be divided into four stages: ① negative Central section heading (from the assembly until after the shield by the end of the segment left out of Dongjing wall only); ② hole Section heading (from the left end of the shield to the shield wall Dongjing end wall 40 m away from Dongjing only); ③ normal section heading (from hole to hole section of the end of paragraph boring boring start); ④ hole section heading (from the shield incision well away from the hole 5 times the outer diameter of play shield into the shield base only).
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