(含：英文原文及中文译文)文献出处：Cocheril Y. Study on Construction Technology of Multi-Arch Tunnel Group in Urban Underground Railway[J]. Journal of Communications, 2015, 3(4):22-32.英文原文Study on Construction Technology of Multi-Arch Tunnel Group in UrbanUnderground RailwayY CocherilAbstractIn this paper, the construction method of the multi-arch tunnel group is discussed by using an engineering example of Metro Line 3. In the construction of the subway, the construction technique of changing a multi-arch tunnel into a single-hole tunnel was first proposed. The technical solutions of the single-middle wall and the separated middle-wall structure were compared and selected to meet the requirements of structural safety, construction safety, and economic efficiency. Good technical solutions can provide reference and reference for the design and construction of similar projects in the future. Keywords: multi-arch tunnel group, single middle partition wall, separated middle partition wall, construction technologyBecause of the design requirements of the subway tunnel, a varietyof tunnel structures are required. Among them, a multi-arch tunnel segment consisting of unequal cross-linked arches and triple-arched tunnels is often used for the connection of the main line and the crossover line. This article combines the project example according to the geological conditions of the tunnel, the time limit requirements through comparison and selection of the best construction program that can achieve rapid construction and save construction costs.1 Project OverviewThe return line of Sports West Road Station on Metro Line 3 is a complex type of return line from Sports West Road Station. In the section , a tunnel group with unequal spans with double arches and triple arches was set up. Unequal cross-arch tunnel excavation span of 20.1m excavation height of 10.076m cross-vector ratio of 1:0.5 hole lining after the lining of 5.2m large-hole lining after the span of 11.4m in the wall thickness of 1.6m. The triple-arch tunnel excavation span is 19.9m and the 7.885m cross-vector ratio is 1:0.1. The surrounding rock of the section of the multi-arch tunnel is from top to bottom: artificial backfill, red sand and alluvial sand layer, alluvial-diluvial earth, fluvial-lacustrine sedimentary soil, plastic residual soil, hard plastic-hard residue. Soil, weathered rock formations, strong weathered rock formations, weathered layers, and weathered layers. Tunnels through the formation of more homogeneous rock strength, strong bearing capacity and stability. Thethickness of the vault covering the tunnel is 15.518m, and the thickness of the surrounding rock layer IV is The buried depth of groundwater in the section of the multi-arch tunnel is , mainly Quaternary pore water and fissure water.2 double arch construction planDue to the complex structure of the multi-arch tunnel section, the tunnel section changes greatly. The construction process is complex and the construction is difficult. The construction period is long. Therefore, it is very important to choose a good construction scheme to complete the construction of the multi-arch tunnel section with high quality and efficiency. When selecting a construction plan, the following aspects are mainly considered: 1 Construction safety and construction Safety 2 Construction difficulty 3 Construction cycle 4 Economic benefits. Based on these four principles, the following two construction plans were selected for comparative selection through the research and demonstration of the construction plan.2.1 Single Wall Construction PlanThe main construction steps and measures of this program are as follows: 1 Prevent the construction of the middle wall from timely construction after the completion of the construction of the temporary construction channel, double-arched and triple-arched intermediate wall from the double-arched tunnel on the right line to the return line side. . 2After the construction of the middle wall lining is completed, the CRD construction method for the right line shall be used for the construction of the large-span tunnel of the re-entry line in accordance with the principle of “small first, large, and closed”. (3) When the construction of the triple-arch tunnel on the side of the re-entry line is carried out, the construction of the triple-arch and double-arched middle wall shall be carried out in accordance with the construction method of the middle-wall of the right line. After the completion of the construction of the four-fold line on the side of the middle wall, the construction of the right line will continue. This construction method is applied to the general construction methods of domestic double-arch tunnels in Guangzhou Metro, Nanjing Metro and Beijing Subway, and can safely and smoothly complete the construction of tunnel groups. However, the study of previous engineering examples and construction techniques can reveal that the program still has shortcomings and defects. 1 This scheme is applied frequently in this project. The initial support and the secondary lining of the tunnel within the short 21.11m multi-arch tunnel will convert 4 times.2 The waterproof layer construction, reinforcement engineering, formwork engineering, and concrete pouring involved in the lining of the middle wall and side tunnels all require multiple conversions and a construction period of up to 2 months. After the completion of the lining, the investment of the anti-bias support of the middle wall and theequipment and equipment will lead to higher construction costs and lower economic benefits.2.2 Separated Wall Construction PlanThe main construction steps and measures of this plan are as follows: 1 Change the unequal span double-arch tunnels into two single holes to change the separation-type mid-rise wall first from the right-line single-line tunnel construction. 2 Double-arched tunnels will not be used for middle-liner lining under single-line conditions. 3 The right-sided large-section double-arch tunnel passes through the side wall of the CRD method. For the 4 fold back line, the construction is performed in the reverse order of the right line. Adopting this scheme is actually a comparison between the two single-line construction methods and the previous one. This has the following advantages: 1 Reduce the number of construction processes and speed up the transition of the process. 2 Reduced the difficulty of construction and shortened the construction period. 3 Reduced construction costs and increased economic efficiency.4 The change to a single wall in the middle of the wall has completely solved the waterproofing defects of the double-arch tunnel structure.5 The construction of the middle tunnel of a triple-arch tunnel is equivalent to a large-span tunnel with reserved core rock, which is conducive to the construction of safety double-arch tunnels on both sides.3 Three Arches Construction PlanFrom the right line directly into the triple-arch tunnel, its supporting parameters are based on the original design, and the entire ring is installed. The whole ring is sprayed on the design and the anchor bar at the middle wall is reinforced. The re-entry side is the same as the right-line construction method. It is necessary to remove a longitudinal reinforcement beam at the junction of the tunnel grille. Strictly control the distance between each step of the excavation footage grid is 0.6m/榀. The middle-wall excavation adopts a weak-weak-weakening blasting scheme to conditionally use the static blasting scheme to minimize the disturbance to the middle-wall rock formation and the lining tunnel to ensure construction safety. The secondary lining is performed immediately after the middle wall excavation is completed. After the completion of the construction of the middle wall, the gaps in the middle walls will be backfilled with jack support. Only one side of the construction is completed before the other side of the wall construction. After the completion of the construction of the middle walls on both sides, the secondary lining of the single-hole tunnels on both sides shall be promptly conducted, and then the excavation and lining of the middle rock mass of the triple-arch tunnel shall be carried out. Special attention should be paid to the settlement and convergence deformation of the triple-arch tunnel at the middle of construction.4 Analysis of structural behavior during constructionChanged the cancellation of mid-walls that do not cross double arches into separated walls. There is no similar engineering design and construction experience in domestic urban subway projects, and there is no similar tunnel structure design. Therefore, whether the structure is safe and whether the construction process is changed during the construction process. Safety will be the focus of this program. Using ANSYS finite element general program software to perform numerical simulations on unequal cross-arch tunnels. The strata-structure model was used to analyze the stress and deformation of the tunnel structure (Fig. 1, Fig. 2, Fig. 3). The horizontal direction of the force taken along the direction of the tunnel is limited to 3 times the hole span. The vertical direction is taken upwards to the surface, and the bottom is 3 times the hole span. Element model Elasto-plastic physical tunnel lining with DP stratum material adopts elasticity The beam element simulation beam elements and solid elements are connected using a coupling equation. It can be seen from the data analysis in Table 2 that the large tunnel has a greater impact on the small tunnel during construction. If the necessary reinforcement measures are taken for the small section tunnel and the longitudinal demolition distance of the temporary support is controlled, this scheme is beneficial and feasible.5 Key Construction Technologies and Corresponding MeasuresThe construction of the multi-arch tunnel section needs to be carriedout under strict construction organization and strong technical guarantee measures. The construction of each construction step is a key to successful construction.5.1 Pulling bolts and reinforcing boltsAfter the removal of the single middle wall, the thickness of the middle wall after the excavation is completed is 0.8m. It is very necessary to set the anchor bolt and the reinforcement bolt. For the tension bolt, the length of the Φ22 steel reel bolt is , and the thickn ess of the middle wall is Reinforced anchor rods are installed at the inverting arch and side wall at both sides of the middle wall with a Φ25 hollow grouting anchor spacing of5.2 Grouting Reinforcement in Middle Wall Rock PillarThe thinnest part of the rock mass in the middle wall is 0.15m. After several blasting excavation processes, the surrounding rock around the middle wall loosens its bearing capacity. Therefore, the loose surrounding rock must be grouted in the vaults, walls and inverted arches of the middle wall. The embedded Φ42 steel pipe slurry adopts a cement-water glass double slurry parameter of 1:1 cement slurry and 3045Be. In the two excavations, the grouting pressure of the inflow glass solution of the middle wall is 0.21.0 MPa. After the final excavation of the grouting line,a saturated grouting is performed on the sandwich wall.5.3 Differential Blasting TechnologyAll the tunnel excavations are drilled and blasted. Because the ground buildings in the downtown area of Guangzhou City are dense and the tunnel is blasted at a distance of “0”, the blasting vibration must be controlled within the allowable range in accordance with the blasting scheme for micro-shock blasting in the reserved smooth layer. The blasting measures taken for Grade III and Grade IV surrounding rocks in the strata of a multi-arch tunnel are as follows: (1) Blasting equipment uses emulsion explosives with low seismic velocity. 2 Strictly control the distance between the perforation of per cycle and the distance between the peripheral blastholes of 0.4m to reduce the charge volume and control the smooth blasting effect. 3 Multi-stage detonator detonation in each blasting The non-electrical millimeter detonator is used to asymmetrically detonate the network micro-vibration technology. 4Second excavation is adopted at the middle wall. 1m is reserved for the smooth surface. Grooves are arranged on the side far away from the middle wall. medicine. The use of artificial wind excavation for excavation of partially dug excavation is prohibited. Through the above-mentioned effective measures, the “0” distance excavation of the multi-arch tunnel was smoothly passed without causing damage to the 0.15-m thick middle wall during the secondary blasting of the middle wall.5.4 Assisted Scissor SupportThrough ANSYS simulation analysis In order to ensure the safety ofsmall-section tunnel construction, it is necessary to assist the reinforcement of the small-section tunnel to withstand the transient impact caused by blasting and the bias generated by the load release during excavation of the rock formation. The support material is welded to both ends of the grid pre-embedded steel plate with I20 steel and the spacing of the support arrangement is 0.6m, ie high strength bolts are used on each grid. The layout of the arrangement was extended to 1.2m on each side of the double arch and completed in front of the big end of the excavation. The height and angle of the support arrangement should ensure smooth construction machinery and equipment. Through the construction proof that the setting of the support is necessary and effective, the small section tunnel converges only 5 mm after the auxiliary scissor is added.5.5 Information ConstructionIn order to ensure structural safety and construction safety, real-time monitoring measurement is carried out during the tunnel construction process. The deformation characteristics of supporting structures and surrounding strata are used to predict the corresponding support structure displacements and to verify the rationality of supporting structures to provide a basis for information construction. Monitoring during construction shows that the maximum settlement of a tunnel with a small cross section is 14.6 mm. The maximum settlement of a tunnel with alarge section is 17.2 mm. The maximum convergence of the tunnel is 7.6 mm. The maximum settlement of the ground is 10 mm. The maximum settlement of the arch with a triple hole arch is 22.8 mm.中文译文城市地下铁道连拱隧道群施工技术研究作者Y Cocheril摘要本文利用地铁三号线某一工程实例对连拱隧道群施工工法进行探讨。