1、 Urban Underground Railroad arch tunnel Construction Technology Group Abstract Project in Guangzhou Metro Line, right-arch construction method of tunnels to explore. Subway Construction in Guangzhou for the first time put forward a double-arch tunnel to single-hole tunnel construction technology, an
2、d a single type of wall and split in the wall structure, comparison and selection of Technology solutions were obtained to meet the structural safety, construction safety and Economic benefits of better Technology solutions for the future design and construction of similar projects to provide refere
3、nce and reference. Keywords: double-arch tunnel group； a single type of wall； construction Technology； split in the wall. As the circuit design requirements subway tunnel, the tunnel structure produces a variety of forms, ranging from cross-section from double-arch and the three-arch tunnel composed
4、 of double-arch tunnel section is commonly used in the connection lines and crossing lines. In this paper, engineering examples, according to tunnel in which geological conditions, duration requirements, raised through the comparison and selection can achieve rapid construction and the purpose of co
5、nstruction cost savings of the best construction programs. 1 Project Overview Guangzhou Metro Line Road station turn-back line of sports for sports Road station after the return line, structure complex, DK3 016.047 037.157 varying cross-section set the double-arch structure, three-arch structure of
6、tunnels. Ranging from cross-arch tunnel excavation span 20.1m, excavation height of 10.076m, cross-vector ratio of 1:0.5, after lining a hole span 5.2m, large holes, after lining span 11.4m, the wall thickness of 1.6 m. Three double-arch tunnel excavation span 19.9m, excavation height of 7.885m, cro
7、ss-vector ratio of 1:0.1. -Arch tunnel section of rock from top to bottom are: artificial fill soil, red - alluvial sand, alluvial - alluvial soil, river and lake facies soil, plastic-like residual soil, hard plastic - a hard-like residual soil, all weathered rock, strong weathering rock, the weathe
8、red layer and the breeze layer. Tunnel through the rock strata are more homogeneous, the intensity high, carrying ability, good stability. Thickness of the tunnel vault covering 15.5 18m, of which grade Wai rock vault thickness 5.6 7.6m. Double-arch tunnel segment groundwater table is 2.28 4.1m, mai
9、nly Quaternary pore water and fissure water. Section 2 dual-arch construction scheme comparison As the double-arch tunnel segment structure more complex, the tunnel cross-section changes in large, complicated construction process, construction was very difficult, the construction cycle is long, so I
10、 chose a good quality and efficient completion of the construction program segment arch tunnel construction is particularly important. Selection of a construction program, the main consideration the following aspects: (1) construction safety and structural safety； (2) construction difficulties； (3)
11、the construction cycle； (4) cost-effectiveness. Based on these four principles, through the construction of research and demonstration program to select the following two programs to compare the selection of the construction. 2.1 a single type of wall construction plan The programs main construction
12、 steps and measures are as follows: (1) The right line of double-arch tunnel hole within the return line side of temporary construction access, dual-arch and the three-arch in the wall construction, is completed in a timely support for the wall, the construction to prevent bias. (2) construction of
13、the wall lining is completed, according to first small then big, closed into a ring principle, the right line with the step method of construction, with CRD engineering method returned a four-lane span tunnel construction. (3) When the return line side of the construction to the three-arch tunnel in
14、 the wall, then in accordance with the right line of the wall construction method and the three-arch-arch in the wall construction, during which the right line to stop excavation until the completion of construction of the wall. (4) The return line side of the wall construction is completed, the rig
15、ht line to continue to move forward the construction. The construction method for the domestic double-arch tunnel of conventional construction method, Guangzhou Metro, Nanjing and Beijing Metro subway both applications, and can secure successful completion of the construction of tunnels. However, ex
16、amples of past engineering and construction Technology research can be found, the program has weaknesses and shortcomings. (1) The program used in this project, in a short span of 21.11m of double-arch tunnel, the tunnels opening between the supporting and secondary lining will be converted four tim
17、es, the conversion too frequently. (2) wall and side holes covered by waterproof layer of tunnel lining construction, steel engineering, formwork, concrete pouring required multiple conversions, the construction period up to 2 months. (3) The lining is completed, the wall of anti-bias materials, equ
18、ipment, support and input, resulting in higher construction costs, Economic efficiency will drop. 2.2 The split in the wall construction plan The programs main construction steps and measures are as follows: (1) ranging from cross-double-arch tunnel into two single-hole, change the formula for the s
19、eparation wall, the first line of one-way right-forward construction of the tunnel. (2) three arch tunnel in the wall to make the first non-Shi lining, according to single-line working condition through. (3) the right line of large-section double-arch tunnel wall construction method adopted in accor
20、dance with CRD. (4) The return line is in accordance with the right line of the opposite side of the construction sequence of construction. Adoption of this program is in fact a one-way in accordance with the construction of two methods, compared with the previous one, after the program has the foll
21、owing advantages: (1) reduction of the construction process to speed up the convergence process conversion. (2) reduce the construction difficulty, shortening the construction cycle. (3) reduce the construction costs and improve Economic efficiency. (4) change a single type of wall to separate the wall, completely solved the structure of double-arch tunnel waterproofing defects.
