厦门轨道交通3号线复杂环境过海区间隧道设计关键技术

第38卷第3期 2018年3月隧遭達银（中奚弍）Tunnel ConstructionVol. 38 No. 3Mar. 2018Key Technology of Sea-crossing Interval Tunnel in Complex Environment Design of Xiamen Rail Transit Line 3SONG Chaoye *, HE Weiguo(China Railway Tunnel Survey & Design Institute Co., Ltd., Tianjin300133, China)A bstract ：A sea-crossing tunnel is generally large in scale, having a complex site environment, and lack of engineering experience. The success of the project is directly related to the design plan. At present, no metro sea-crossing tunnel havd been built in mainland, and the design standard and technology of the sea-crossing tunnel are not studied throughly. The key technology of long and large sea-crossing metro tunnel design，including construction method selection, cross-section design, waterproofing and drainage system design, response to complex environment in sea area, durability design, ventilation and evacuation are analyzd with methods of geological analysis, engineering analogy and comprehensive comparison based on the sea-crossing tunnel of Xiamen Rail Transit Line 3. A combination of shield and mining methods is proposed for the geological conditions of different sections. The drainage system of the mining section can be maintained by applying advanced grouting to control displacement. The complex geology of the sea area is considered in the targeted design, including a deep weathering trough, a water-rich sand layer, a hard rock and uneven stratum, and the development of solitary rocks. The durability design of the tunnel structure and the limit of the bearing capacity are treated equally to consider safety reserve. The tunnel adopts sectioned longitudinal ventilation and smoke extraction m ode, and contains ventilation shafts and civil smoke extraction air shafts on shore to prevent disasters. The conclusions can provide technical support for tunnel scheme decision and reference for similar projects.K e y w o rd s：metro tunnel；sea-crossing tunnel；shield method and mining method combination；waterproofing and drainage ；durability ；disaster prevention and evacuationDOI：10. 3973/j. issn. 2096-4498.2018.03.009中图分类号：U 452文献标志码：A文章编号：2096-4498(2018)03-0414-10厦门轨道交通3号线复杂环境过海区间隧道设计关键技术宋超业*，贺维国(中铁隧道勘测设计院有限公司，天津3〇0133)摘要：过海隧道一般规模大，场地环境复杂且工程经验缺乏，设计方案优劣直接关系到工程的成败B目前内地尚无建成的地铁过 海区间隧道，对过海区间的设计标准和技术研究较少。

文章以厦门轨道交通3号线过海区间为工程背景，采用地质分析、工程类比 和综合比选的方法，对长大过海地铁区间的设计关键技术，包括工法选择、断面设计、防排水设计、海域复杂地质应对、耐久性设计、防灾通风及疏散等进行分析。

提出结合不同区段地质情况采用盾构法和矿山法组合的工法；矿山法段防排水考虑超前注浆控制 排水量，采用可维护排水系统；海域复杂地质段(包括风化深槽、富水砂层、硬岩及软硬不均地层、孤石发育等）采取针对性设计措 施；隧道结构的耐久性设计与承载力极限设计并重对待，考虑预留补强空间；隧道防灾采用分段纵向通风排烟模式，设置岸边通风 竖井和土建排烟风道。

研究成果可为区间方案决策提供技术支持，并为类似工程实施提供借鉴。

：关键词：地铁区间；海底隧道；盾构矿山组合法；防排水；耐久性；防灾疏散*Corresponding author. E-m ail：geyesky@ 126. com第3期SONG Chaoye, et al ：Key Technology of Sea-crossing Interval Tunnel in Complex Environment Design of Xiamen Rail Transit Line 34150 IntroductionWith the rapid development of the seaside city construction and the improvement of the public transportation service, the demand for sea-crossing tunnels has increased considerably. At present, the main construction methods of sea-crossing tunnels are the mining, shield and immersed tube methods. The key to the success of the project is the key technology in the design of a tunnel, which is a large-scale project with huge investment and a high risk ⑴.As early as the mid- 1930s, developed countries began to construct subsea tunnels, such as the shield tunnel of Japan Kan-Mon Tunnel and the Netherlands Rotterdam immersed tunnel. In the year 1988, Japan completed the longest tunnel in the w orld, Seikan Tunnel, with a total length of 54 km[23，by using the borehole-blasting method on the Tsugaru Strait. The representative subsea tunnels constructed using the shield method include the 49. 2-km- long Anglo-French Channel Tunnel and the 7. 9-km-long Danish Strait Project, and both of them are railway tunnels with a double-tube diameter of 8. 5 m in the circular cross-section^3-4^.In China, Liuyang River Tunnel of Wuhan-Guangzhou High-speed Railway^5^, constructed by mining method, is the first underwater high-speed tunnel, with a span of 14.8 m and excavated cross-section of 170 m2. Shiziyang Tunnel of Guangzhou -Shenzhen -Hong Kong High-speed Railway is the longest underwater high-speed railway tunnel in China with a length of 10. 8 km. The technology, " shield tunneling in the opposite direction, docking below the ground surface, and dismantling in the tunnel" , was adopted for the construction of this tunnel firstly [6] •The five sea-crossing tunnels built in Hong Kong were constructed by the immersed tube method using round steel pipe and rectangular concrete pipe segments[7]. Qingdao Metro Line 1and Xiamen Rail Transit Line 2 and Line 3 crossing the sea are currently under construction. Therefore, the construction of large sea-crossing tunnels needs to be demonstrated in detail. The related studies focus on the feasibility analysis, construction, bridge and tunnel selection, and route selection [7 _ 11 ]. Q u[12]introduces the characteristics and difficulties of the construction of Xiamen Xiang7 an Tunnel, the first undersea tunnel in mainland. References [13-15 ] introduce the construction technology of a subsea tunnel, such as grouting,calculation of water pressure, and prefabrication of an immersed tube tunnel, while there are few papers on the key technology of sea-crossing metro tunnel design. In this paper, the detailed key technology of the design of a super long sea-crossing metro tunnel in a complex environment is presented in combination with the specific project of Xiamen Rail Transit Line 3 , which provides a reference for similar projects.1 Project profile1.1 Interval design overviewsThe Wuyuan Bay Station-Liuwudian Station Section of Xiamen Rail Transit Line 3 crosses Xiamen eastern waters, which is located on the northwest side of the Xiang^an Sabsea Tunnel,connects the island to Xiang^an District. The length of the interval is 4. 95 km, and the length of the intersection across the sea is approximately 3.6km. The interval is a double-direction lin e, the maximum design speed is 80 k m/h, and six cars are grouped in type B vehicles. One inclined shaft, one ventilation shaft, ten service channels, and three waste water pumping houses and substations are set in the interval. The interval of Wuyuan Bay Station-Li uwudian Station is shown in Fig. 1.1.2 Geological condition and environment(1)The cross-sea section crosses the coastal accumulation area, and the terrain of the inland and the outer continental segment is flat; the depth of the sea area is from 20 m to 25 m.(2)The geological conditions of the interval crossing strata are complex. The islands of Xiamen and Xiang;an bedrock are at at low elevation, while the bedrock scar of the most moderately and slightly weathered sea regions fluctuates considerably, and there are rocks, reefplates,416隧遭逢钹（中其夂)第38卷and weathered deep troughs.(3 ) The tunnel sea area passes through four groups of deep troughs of fault weathering. The weathering trough is mainly composed of completely weathered granite and scattered and cracked strongly-weathered granite, which contains dense sand and gravel mixed clay.(4 ) The groundwater is a mainly cataclysmic strong weathering zone and includes the fissure water of the bedrock below. The permeability of other strata is poor, except for the sand bed and the possible water-rich bedrock fracture zone in the sea area.(5)The sea area passes through the slightly-weathered granite layer and deep weathered trough. The strength of the slightly-weathered bedrock is between 63. 5 MPa and 204. 2 MPa, with average strength 110 MPa, and the rock strength is high. The Xiangr an side tunnel mainly passes through sand layer, p eb b le, and fully-weathered stratum, with strong permeability and is connected with the sea water. The suggested values of the rock and soil parameters are shown in Table 1.(6)Marine chloride corrodes the environment, and the environmental action grade is IH -E.(7)The crossing sea area is the core protection area of Chinese White Dolphin. The surface pipeline is dense and complex in the island, and Xiang’an is formed by reclamation, which requires high environmental protection.1.3 Design features and standards(1)The tunnel secsion crossing the sea area is 3.6km long with a high construction risk and a high standard of disaster prevention and evacuation during operation.(2)The tunnel is deeply buried and bears high water pressure. The maximum depth of the sea-crossin sectionis 25 m, and the maximum buried depth of the tunnel is69 m.(3)The designed service life of the main structure is 100 years.(4)The waterproofing grade of structure is Grade II -(5)The seismic intensity of interval structure is constructed auording to Intensity 7，and the seismic structural is constructed according to Intensity 8.Table 1Suggested values of rock and soil parameters Density/(g/cm3 )Cohesion/kPaInnerfrictionangle/ (。