Key Construction Technology of Shield Tunneling Crossing Underneath a Railway
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infrastructures Article Key Construction Technology of Shield Tunneling Crossing underneath a Railway Jinjin Ge 1,*, Ying Xu 2 and Weiwei Cheng 1 1 School of Civil Engineering and Architecture, Anhui University of Science and Technology, Huainan 232001, China; [email protected] 2 Key Lab of Coal Deep-Well Structural Technique, Huaibei 235000, China; [email protected] * Correspondence: [email protected]; Tel.: +86-554-666-8652 Academic Editors: Higinio González-Jorge and Pedro Arias-Sánchez Received: 14 August 2016; Accepted: 4 November 2016; Published: 10 November 2016 Abstract: The shield tunnel of the Kunming subway crosses beneath the Kun-Shi Railway. Due to the high requirements of railway track for settlement control, this article proposes the following technical measures for controlling the settlement based on the analysis of risks arising from the shield crossing railway: (1) Reinforcing the stratum of the region crossed by the shield in advance to achieve high stability; (2) Using a reinforced segment for the shield tunnel and increasing reserved grouting holes for construction; (3) Reasonably configuring resources, optimizing construction parameters, strengthening monitoring and information management during the shield crossing. In strict accordance with the construction plan, the shield successfully and safely crossed beneath the Kun-Shi Railway; this provides experience that can be used in similar projects in the future. Keywords: subway tunnel; crossing railway; shield method; construction technology 1. Introduction Common tunneling methods include: open-cut method, cover and cut (top-down) method, spray anchor subsurface excavation method and shield method. However, subway lines always pass beneath the downtown areas with heavy traffic and many economic activities, so it is necessary to reduce the impact of tunnel construction on the ground. Compared to other methods, shield construction does not affect ground traffic and underground pipelines, so the shield method is often used for subway tunnel excavation [1–6]. The history of tunnel construction with the shield method goes back more than 150 years. The first study was conducted by French engineer Marc Isambard Brunel [7,8]. In 1818, he began to study the construction of the shield method. In 1825, with a rectangular shield, he built the world’s first underwater tunnel (11.4 m wide, 6.8 m high) under the Thames in London. Although there are some unavoidable disadvantages in the shield method, such as: (1) Poor adaptability in the changing of section size; (2) Expensive purchase cost of the new shield, meaning the engineering of a short section construction is uneconomic; (3) Poor working environment of the workers, it is widely used because of its obvious advantages, such as: (1) Adequate construction safety for excavation and lining operation under the protection of the shield; (2) Underground construction not affecting the ground transportation and construction at the bottom of the river not affecting river navigation; (3) The construction operation not affected by climatic conditions; (4) The vibration and noise caused by the shield harming the environment less; (5) Small influence on the ground buildings and underground pipelines. The shield tunneling method was used for tunnel excavation in Kunming Rail Transit Line 3, which needed to cross beneath the running Kun-Shi Railway during the construction process. The Kun-Shi Railway was one of the first railway lines built in China, and it has greatly contributed Infrastructures 2016, 1, 4; doi:10.3390/infrastructures1010004 www.mdpi.com/journal/infrastructures Infrastructures 2016, 1, 4 2 of 10 Infrastructures 2016, 1, 4 2 of 10 Kun-Shi Railway was one of the first railway lines built in China, and it has greatly contributed to the research of the development of China’s railways. It is classified as a Grade I Cultural Relic in toYunnan the research province. of the Therefore, development the railway of China’s tracks railways. were required It is classified to be protected as a Grade during I Culturalthe construction Relic in Yunnanof shield province. crossing, Therefore, greatly increasing the railway the tracks difficulty were of required construction. to be protectedIn addition, during risks the existing construction in the ofconstruction shield crossing, of shield greatly crossing increasing included: the difficulty(1) Large uplift of construction. and settlement In addition, of ground risks surface existing resulting in the constructionin uneven subgrade of shield which crossing caused included: traffic(1) accidents; Large uplift (2) Impact and settlement of train runnin of groundg on the surface annular resulting tunnel; in uneven(3) High-risk subgrade ground which monitoring; caused traffic (4) Uplift accidents; and settl (2)ement Impact of ofground train runningsurface caused on the by annular interruption tunnel; (3)of High-riskshield tunneling. ground To monitoring; ensure the (4) safety Uplift of and the settlementrailway and of shield ground tunnel surface during caused construction by interruption and ofoperation, shield tunneling. a rigorous To reinforcement ensure the safety scheme of the was railway prepared and prior shield totunnel shield duringtunneling construction based on the and operation,domestic research a rigorous and reinforcement analysis of settlement scheme was cont preparedrol [9–15]. prior Facts to shieldproved tunneling that this basedscheme on was the domesticfeasible. research and analysis of settlement control [9–15]. Facts proved that this scheme was feasible. ThisThis article article introduces introduces thethe keykey constructionconstruction technologytechnology of shield crossing railway railway based based on on the the successfulsuccessful construction construction of of a shielda shield crossing crossing for thefor Kun-Shithe Kun-Shi Railway Railway to provide to provide a reference a reference for relevant for engineeringrelevant engineering practice. practice. 2.2. ProjectProject Overview 2.1. Project Introduction 2.1. Project Introduction TwoTwo Komatsu Komatsu single-circular, single-circular, mudding mudding typetype EarthEarth Pressure Balanced (EPB) [16] [16] shield shield machines machines φ ofof φ6.34 6.34 m m were were used used for for tunneling tunneling in the in westthe west section section of Mianshan of Mianshan Station-Shagouwei Station-Shagouwei Station-Xiyuan Station- LijiaoXiyuan Station Lijiao section Station of section Kunming of Kunming Rail Transit Rail LineTransi 3.t TheLinenormal 3. The normal line spacing line spacing was 13.4 was m. 13.4 The m. tunnel The liningtunnel was lining designed was designed with an with external an external diameter diameter of 6.2 of m, 6.2 internal m, internal diameter diameter of 5.5of 5.5 m andm and ring ring width width of 1.2of m.1.2 Them. The shield shield crossed crossed beneath beneath the the Kun-Shi Kun-Shi Railway Railway in in the the section section of of YCK9 YCK9 + 030–060.+ 030–060. ThisThis project project started started fromfrom thethe MianshanMianshan StationStation near the Dian Ren Association south south of of Renmin Renmin WestWest Road Road and and advanced advanced towards towards the the easteast alongalong RenminRenmin WestWest Road.Road. The section of YCK9 + + 030–060 030–060 ◦ crossedcrossed thethe Kun-ShiKun-Shi RailwayRailway byby 3434° throughthrough the crossing of Renmin West West Road Road and and Changyuan Changyuan MiddleMiddle RoadRoad to the the Shaweigou Shaweigou Station Station near near the the Yunnan Yunnan Ruidian Ruidian Economic Economic and Trade and Trade Co., Ltd. Co., Both Ltd. Bothshield shield machines machines were were transferred transferred at the at theShaweigou Shaweigou Station. Station. Starting Starting from from the theend endwell well in the in theeast east of ofShaweigou Shaweigou Station, Station, the the two two shield shield machines machines advanc advanceded towards towards the east the along east alongthe Renmin the Renmin West Road West Roadand passed and passed Dongjiagou Dongjiagou and Haiyuan and Haiyuan River Rivercourse, course, finally finally arriving arriving at the atXiyuan the Xiyuan Lijiao LijiaoStation Station near nearLianyuan Lianyuan Filling Filling Station. Station. TheThe central central section section ofof thethe railwayrailway throughthrough whichwhich thethe shieldshield tunneled was YCK9 + 032. 032. The The section section withinwithin 30 30 m m before before and and after after thethe junctionjunction ofof thethe railwayrailway andand tunneltunnel was affected by by the construction construction withwith about about 10 10 days days of of shield shield crossing.crossing. TheThe shieldshield machinemachine tunneled through the the left left line line from from 1 1 February February toto 1010 FebruaryFebruary and tunneled tunneled through through the the right right lin linee from from 1 March 1 March to 10 to March 10 March at a low at a speed. low speed. The Therelationship relationship between between the shield the shield tunnel tunnel and Ku andn-Shi Kun-Shi Railway Railway is shown is shown in Figures in Figures 1 and 12. and 2. y wa ail i R Sh n- Ku Renmin West Road Shield hanging out well FigureFigure 1.1. Kun-shiKun-shi railwayrailway and subway tunnel location. InfrastructuresInfrastructures2016 2016, 1,, 1 4, 4 3 of3 10 of 10 Kun-Shi Railway Interval left line Interval right line Figure 2. Figure 2.Kun-Shi Kun-Shirailway railway andand the subway tunnel tunnel cross cross section section relationship. relationship.