双车道公路盾构隧道管片合理分块型式研究

文章以双车道公路盾构隧道为例,设计了三种不同分块型式的管片结构,并采用梁-弹簧模型模拟装配式管片结构,借助于有限元法分析了在不同拼装方式下管片结构的力学特性;通过对内力和变形的分析比较,并综合考虑设计、施工及其造价等因素,认为在最不利荷载作用下的管片结构宜采用10块分块型式;管片结构的正负弯矩值相差很大,故宜将内外两侧的钢筋分开进行配筋设计。     

膨胀土地层中盾构隧道管片结构受力分析与对策研究

针对成都地铁2号线部分区间穿越由粘性土、卵石、泥岩组成的膨胀性地层的工程实践,采用数值模拟的方法计算和分析了在膨胀土位于管片结构周围不同位置时,在不同的膨胀接触压力下,管片结构的变形和内力情况.计算结果分析表明:当膨胀土位于隧道下方或上方时,膨胀土的膨胀将会增大管片结构的变形和内力,对于这类区段,隧道设计上应增加配筋量或采用通缝拼装方式;施工上要避免引起周围地下水位发生变化,应增强管片防水性及保证注浆质量.     

海相地层地铁盾构隧道钢筋钢纤维混凝土管片可靠度研究

地铁盾构隧道管片材料的选取决定了管片性能与结构的整体安全度与可靠度,钢纤维混凝土材料在抗裂、抗震、抗疲劳、抗冲击等方面具有比普通混凝土更好的力学特性。为此,文章针对深圳地区海相地层地铁盾构隧道管片衬砌,基于可靠度理论,在混凝土材料中加入钢纤维,优化配合比设计,并通过系列试验开展了钢筋钢纤维混凝土管片可靠度研究。结果表明:(1)在盾构隧道不出现大变形的前提下,以少配筋加钢纤维混凝土管片为最佳选择方案;(2)在配筋率相同时,少筋加钢纤维混凝土管片比原配筋混凝土管片具有更高的可靠度,且受钢纤维的掺量、品种、形状和长径比等因素综合影响;(3)钢筋钢纤维混凝土管片能极大提高盾构隧道管片衬砌结构的可靠度指标,满足海相地层地铁隧道结构耐久性的安全标准。     

盾构扩挖法建造地铁车站的监测方案设计

盾构扩挖法建造地铁车站可以解决区间盾构施工和车站施工在工期上的矛盾。选取北京地铁十号线三元桥车站起始里程18.6m范围作为试验段,开展了盾构法与明挖法结合建造地铁车站的方案研究。为了确保试验段安全顺利地施工,同时为以后推广此类车站的设计和施工收集试验数据,特编制本监测方案,包括施工安全监测和试验数据监测。针对试验段的特殊情况,重点对盾构管片位移与变形、管片张开度、基坑外地表沉降、土体位移、基坑土钉支护墙水平位移、支撑轴力、节点处结构应力和管片内力进行了监测设计。     

软土盾构隧道施工阶段上浮计算模型探讨

文章首先对管片上浮作用机理进行了分析,确定了盾构隧道施工阶段上浮计算模型荷载分布规律和计算方法;其次指出了弹性支撑法和修正惯用法直接运用于盾构隧道上浮阶段设计所存在的问题,即弹性支撑法计算得到管片底部向下位移,与实际上浮阶段管片隆起不符,而修正惯用法又不能考虑拱顶上覆土体反向压缩特性;最后,基于弹性支撑法并利用修正惯用法思想提出了能规避上述两个问题的反转抗力力学模型。结果表明:提出的计算模型与施工阶段管片上浮变形特征吻合度高,施工阶段管片上浮状态下弯矩、轴力和剪力最值较弹性支撑法和修正惯用法获得的结果分别增加68%、21%和51%以及34%、69%和22%,说明按本文推荐计算模型进行上浮管片设计可避免实际工程配筋不足造成的管片破损、开裂或渗漏。其结论可为盾构隧道设计提供一定理论支撑和参考。     

9块等分管片设计及其工程应用研究

文章就城市双车道公路盾构隧道设计了一种9块等分管片,采用有限元法进行了管片结构内力和变形分析.分析结果表明,9等分管片的受力合理,管片结构的内力和变形都满足设计要求.管片一环9块等分有利于优化配置运输能力和管片拼装机械手的拼装能力,同时减少管片的接头数量,增加隧道衬砌的防水能力,值得在我国城市双车道公路盾构隧道中推广应用.     

武汉长江隧道盾构施工段衬砌管片方案设计

结合武汉长江隧道盾构施工段的衬砌设计,对管片环结构、管片分块方案、管片环宽等关键设计参数进行计算分析,提出合理的管片方案。     

关于盾构隧道管片尺寸的解析

目前盾构隧道管片尺寸设计普遍采用AutoCAD等辅助设计软件作图的方法来完成,设计时或采取某些近似处理或过程比较麻烦,其结果也不便于校核。文章根据解析几何知识并结合管片构造特点推导了管片尺寸相关的解析公式。分析表明,采用该方法既可得到管片尺寸的精确解,也能通过程序计算提高设计效率,且便于校核作图结果。     

装配式管片接头受力平面有限元分析

在盾构法隧道设计中,评价接头刚度对管片内力的影响是隧道设计的一个十分重要的内容.由于管片接头或整环管片试验资料过少,很难得到普遍性的接头刚度规律.目前工程中大多根据经验将接头刚度确定为某一常数.针对上述问题,文章通过对广州地铁三号线无传力衬垫的盾构隧道管片接头进行了接触问题的非连续弹塑性有限元分析,得出了接缝转角与弯矩的关系曲线.这种关系曲线接近双直线形状,因此可以简化为双直线关系来确定接头刚度.计算的结果反映出管片接头转角与管片内力之间的非线性关系的规律,为管片设计中的关键参数选择提供了依据,具有较大的实用和参考价值.     

地铁管片隧道防迷流设计及测量

本文对地铁管片隧道的防迷流设计原理，管片的防迷流制造工艺以及管片的防迷流电气特必的测量方法作了详细介绍。     

Indoor air quality and passenger thermal comfort in Beijing metro transfer stations

In this study, particulate matter was investigated as the primary pollutant in the air quality of Beijing Metro transfer stations, and passenger thermal comfort during the transfer process was evaluated by using the relative warmth index (RWI). Passenger thermal comfort level is not ideal in 87% of the measured space and is slightly hot overall, with an RWI range of 0.20–0.43. Although 20% of the measured space has lower values than ASHRAE’s cooling comfort class, the thermal comfort level of most measured space is good in winter morning rush hours, with an RWI range from −0.18 to 0.28. The particulate matter (PM) concentration is related not only to the season and spatial depth but also to the transfer design of the metro station. During the morning rush period, the concentration ranges difference of PM₁₀ and PM_2.5 in winter are 262.9 μg/m³ and 125.5 μg/m³, respectively, which are 1.43 and 1.46 times higher than those of in summer. There are significant differences in the PM concentration and RWI values between the island and lateral platforms of Beijing Metro transfer stations, and the design of the lateral platform is superior to that of the island platform. Another exploratory experiment is conducted to determine if the PM concentration has a potential effect on human metabolic rate. The data in this paper provide a valuable reference for further comfort research and environmental control in metro station, and the conclusions may guide the further underground space design of metro transfer stations.     

大跨地铁暗挖车站施工地层变位控制技术研究

在城市中修建地铁暗挖车站,由于开挖跨度大,埋深浅,对地层扰动较大,地表沉降的控制往往成为工程的重点和难点。北京地铁五号线某车站施工时采用数值分析预测、地层变位分部控制,以及信息化施工等措施,成功地将地表沉降控制在设定范围。其研究方法和支护手段,对解决类似大断面暗挖施工具有一定的指导和借鉴意义。     

概述地铁工程中的人防设计

地铁作为城市人防总体规划的重要组成部分,战备效益显著,但目前国家尚无一个针对地铁人防的设计规范。结合北京、上海、深圳的地铁人防设计,论述人防设防标准的同异内容,探讨制订统一规范的必要性;提出在确保战备效益的前提下,人防设计要立足兼顾经济效益和社会效益最大化的原则。     

上海人民大道过街地道设计施工中的地铁保护措施

基坑工程的实施往往会对周边已建或在建的地铁车站及区间隧道产生影响，针对这一问题，介绍了上海市人民大道过街地道扩建工程中采用的一系列地铁保护、控制区间隧道变形、确保地铁正常运营的技术措施和效果。     

The impact of metro services on housing prices: a case study from Beijing

Assessment of the impact of metro systems on housing prices is important for financing transport infrastructure via value capture. This paper provides evidence for this relationship, focusing particularly on the effects of metro services, and uses the large city of Beijing, China, as a case study. A spatial error model was applied to 2835 samples of online property sales data obtained in January 2016. Three transport service indicators associated with metro transfers and waiting times were explored: (1) metro headway, (2) access to different metro lines and (3) accessibility to employment opportunities. The results show that areas with more employment opportunities via public transit have higher housing prices than other areas. Shorter metro headways are positively related to housing prices near stations. Housing prices for neighborhoods having access to more than one metro line within 800 m-buffer area are higher than those without access to metro lines, controlling for number of accessible jobs within 30 min. This study sheds light on the importance of metro services on housing prices. It has implications for further research and for the planning policies of metro-dependent cities.

     

地铁下穿既有线和扩大基础桥梁施工方案研究

北京地铁六号线朝阳门—东大桥区间隧道下穿既有地铁二号线朝阳门站和二环主路朝阳门桥施工,工程难度极大,施工安全控制极为重要。为研究新建隧道施工过程对围岩与既有结构的影响,保证施工期间既有结构的安全使用、有效控制地表沉降,针对本工程拟定了不同施工方案并采用有限元计算软件MIDAS-GTS进行三维仿真模拟,分析其对围岩与下穿建筑物的变形控制效果。依据既有结构沉降控制标准,最终提出采用新建隧道与既有车站零距离刚对刚接触、自隧道两侧同时开挖、在既有车站两侧同时施做水平旋喷桩的方案。该方案将为六号线下穿既有车站和扩大基础桥梁的设计与施工提供理论依据。     

A stochastic model for the integrated optimization on metro timetable and speed profile with uncertain train mass

The integrated timetable and speed profile optimization model has recently attracted more attention because of its good achievements on energy conservation in metro systems. However, most previous studies often ignore the spatial and temporal uncertainties of train mass, and the variabilities of tractive force, braking force and basic running resistance on energy consumption in order to simplify the model formulation and solution algorithm. In this paper, we develop an integrated metro timetable and speed profile optimization model to minimize the total tractive energy consumption, where these real-world operating conditions are explicitly considered in the model formulation and solution algorithm. Firstly, we formulate a two-phase stochastic programming model to determine the timetable and speed profile. Given the speed profile, the first phase determines the timetable by scheduling the arrival and departure times for each station, and the second phase determines the speed profile for each inter-station with the scheduled arrival and departure times. Secondly, we design a simulation-based genetic algorithm procedure incorporated with the optimal train control algorithm to find the optimal solution. Finally, we present a simple example and a real-world example based on the operation data from the Beijing Metro Yizhuang Line in Beijing, China. The results of the real-world example show that, during peak hours, off-peak hours and night hours, the total tractive energy consumptions can be reduced by: (1) 10.66%, 9.94% and 9.13% in comparison with the current timetable and speed profile; and (2) 3.35%, 3.12% and 3.04% in comparison with the deterministic model.     

A two-stage stochastic optimization model for the transfer activity choice in metro networks

This research focuses on finding the best transfer schemes in metro networks. Using sample-based time-invariant link travel times to capture the uncertainty of a realistic network, a two-stage stochastic integer programming model with the minimized expected travel time and penalty value incurred by transfer activities is formulated. The first stage aims to find a sequence of potential transfer nodes (stations) that can compose a feasible path from origins to destinations in the transfer activity network, and the second stage provides the least time paths passing by the generated transfer stations in the first stage for evaluating the given transfer schemes and then outputs the best routing information. To solve our proposed model, an efficient hybrid algorithm, in which the label correcting algorithm is embedded into a branch and bound searching framework, is presented to find the optimal solutions of the considered problem. Finally, the numerical experiments are implemented in different scales of metro networks. The computational results demonstrate the effectiveness and performance of the proposed approaches even for the large-scale Beijing metro network.     

引进装配式铺盖法修建地铁车站

针对城市地铁车站建设过程中对道路交通影响的问题,介绍了一种对路面交通影响较小的施工方法——装配式铺盖法,并对其五大特点作了分析。结合北京地铁9号线工程实施该项技术的实例,提出了推广装配式铺盖法的建议和设想。     

兰州地下轨道交通围岩热物理参数试验研究

地下轨道交通暖通空调系统的优化设计与地下轨道交通隧道围岩的热物理参数性质密切相关。文章以兰州地下轨道交通原状土样为研究对象,使用Hot Disk热常数分析仪探究了兰州地下轨道交通围岩的热物理性质。研究结果表明:兰州地下轨道交通围岩土样的导热系数随深度的增加而增加,深度13 m处的中砂层导热系数和热扩散系数最大,明显比其它深度处的黄土层和淤泥质土层的导热系数和热扩散系数大,而中砂层体积比热较小;围岩土样的导热系数随含水率增加呈线性增长,体积比热随含水率增加先降低后增高,热扩散系数随含水率增加先升高后缓慢降低。