苏通1000 kV交流特高压综合管廊工程盾构隧道接缝防水试验研究

淮南—南京—上海1 000 kV交流特高压苏通GIL综合管廊工程是大直径盾构法隧道与特高压输电线路的首次结合,穿越长江,隧道结构承受的最高水压达到79.8 m,是国内水压最高的盾构法隧道。结合大直径盾构隧道接缝防水实践经验和本工程特点,设计拟定了接缝防水构造与密封垫备选断面形式;分别开展通缝拼装及错缝拼装方式下管片衬砌结构防水性能数值模拟和室内试验,得出了不同错缝量、不同张开量情况下的抗水压值和装配应力,判定能否满足本工程的防水要求;最终确定了防水材料性能指标及密封垫断面结构。     

武汉长江隧道管片接缝防水密封垫设计与试验研究

武汉长江隧道为我国首次穿越长江江底的大型重点工程,投资巨大,工程宏伟。对于盾构隧道管片接缝防水是隧道防水的关键,直接影响到隧道的防水效果和隧道的耐久性,通过本项目的实验研究,确定了满足工程耐水压性能、装配性能要求的防水密封垫。采用国内外的理论与实践经验,进行管片接缝防水密封垫初步设计,然后模拟施工极限装配误差,对初步设计进行防水性能与装配性能实验。根据实验结果对防水密封垫断面尺寸与结构形式及材料进行优化,并最后确定满足工程要求的最优的防水密封垫设计。因此,对于管片接缝密封垫设计,通过防水性能与装配性能实验优化设计应该成为设计中的重要步骤,对保证管片密封垫防水性能及管片拼装质量具有重要的意义。     

周家嘴路越江隧道管片接缝防水技术研究

针对上海周家嘴路越江盾构隧道工程防水要求高、隧道纵向变形大等难点,文章采用有限元数值模拟和试验分析等手段,对盾构隧道管片接缝防水技术进行量化分析和研究,确定了接触面应力和闭合压缩力均符合设计防水要求的弹性密封垫方案,并提出了密封垫防水槽位置优化、减少接缝错台量、加强角部防水能力等防水构造措施。结果表明,该弹性密封垫设计方案合理可行,采取的防水技术措施切实有效。     

软弱地层中大断面矩形盾构法隧道密封垫防水性能试验研究

矩形盾构法隧道具有空间使用率高,可进行浅覆土、长距离曲线掘进施工的特点,为地下连接通道的建设提供了新的建设方法,具有广泛的应用前景。以上海虹桥临空11-3地块地下连接通道工程为背景,结合矩形盾构法隧道的变形特点,对工程中所使用的弹性橡胶密封垫开展了防水性能试验。与大深度圆形盾构法隧道相比,矩形盾构法隧道埋深浅,不同于以往追求弹性橡胶密封垫的最大防水能力,本次从弹性橡胶密封垫适应变形的角度开展了相关试验;依据试验结果确定了弹性橡胶密封垫的硬度,工程实践表明隧道防水性能良好。     

高速铁路盾构隧道防水设计

根据高速铁路的运营养护特点,在广深港高速铁路狮子洋隧道设计过程中提出了盾构管片接缝防水采用双道密封与分区隔断的防水技术方案.文章针对弹性密封垫防水特点,分析了弹性密封垫及分区防水的关键技术参数,并针对弹性密封垫的正常工作状态,提出了接缝的错台量、张开量及施工期沟槽修补要求.     

盾构隧道管片接缝防水技术的新认识

盾构隧道防水工程中,无论是管片接缝密封垫的材质选择、断面构造、加工工艺,还是选择设置单道或双道橡胶密封垫,都是探究的关键。根据盾构隧道接缝防水技术现状以及管片接缝防水新技术,从密封垫材质(弹性橡胶、遇水膨胀橡胶及复合橡胶)的选用及加工方式(模压、挤出微波硫化)入手,对单道、双道密封垫在不同隧道类别、不同使用条件下的应用技术进行分析研究,在对劣质密封垫或受损密封垫的取代等设计与应用提出新认识的同时,也对嵌缝、注入密封剂、传力衬垫等接缝防水或相关技术中的误区作了进一步揭示、剖析。     

错缝拼装盾构衬砌结构力学性能试验分析

错缝拼装盾构隧道衬砌结构由于存在环间传力行为,具有与通缝拼装衬砌结构不同的力学特性。文章通过三环压弯试验获得错缝拼装管片的极限承载力和力学行为规律,分析了衬砌结构纵缝、环缝及管片本体的相互协同作用,并通过一系列试验设计工况得到了纵向力和荷载水平对结构性能的影响规律。同时对比分析了三环与单环压弯试验结构的受力特性和破坏模式的差异,获得错缝拼装盾构衬砌的力学性能和环间传力效应。     

关于盾构法隧道采用错缝拼装技术的探讨

衬砌管片的错缝拼装技术由于其在隧道变形与防水控制方面的优越性,以及建立在该技术基础之上的一系列盾构自动化施工控制与管片制造技术的发展,使得隧道的施工效率与质量大大提高,在国外隧道工程,尤其是在变形和防水要求较高的隧道工程中得到广为应用.文章从几个方面对盾构法隧道错缝拼装方式进行了介绍,并指出了当前对错缝拼装衬砌受力机理及使用性能进行研究的必要性以及所要解决的问题,有利于澄清目前在应用错缝拼装技术上存在的种种认识上的误区,起到抛砖引玉的作用.     

快速接头盾构隧道衬砌结构设计参数研究

管片接头受力性能是影响盾构隧道衬砌结构设计参数的关键因素,而采用快速连接件的接头受力性能尚不明确。文章参考国外盾构隧道衬砌快速连接件的研究和应用情况,结合上海市天然气管线过江隧道工程,通过管片接头荷载试验,对快速接头的纵缝转角刚度、纵缝抗剪刚度、环缝抗剪刚度进行研究。结合试验结果建立了基于梁弹簧法的三环错缝分析模型,给出了该模型关键参数的具体取值范围。最后通过计算对比提出了该种快速接头盾构隧道衬砌结构的修正惯用模型设计参数——刚度折减系数、弯矩传递系数。     

盾构隧道新型衬砌结构设计参数试验研究

盾构隧道衬砌结构由管片和接头组成,接头的形式直接影响盾构隧道的整体力学性能。上海轨道交通18号线盾构隧道新型衬砌结构环间采用新型插入式快速接头,块间采用新型滑入式快速接头。针对错缝拼装的新型衬砌结构,分别进行了整环足尺试验,介绍和分析了新型衬砌结构的受力性能;通过计算给出不同埋深、不同侧压力、不同纵向力下修正惯用法设计计算参数的取值。     

Survey of R&D in PRT systems

A survey of research and development in advanced transit has been made by Chalmers University of Technology in Gothenburg in cooperation with Trans21 in Boston. Summary findings are reported for fourteen academic research programs and ten development programs for PRT. An earlier version of this paper was presented at the International Conference of PRT and other Emerging Systems held in Minneapolis in 1996.     

管道风险分析指数评分法中分值调整初探

管道风险分析指数评分法中重要步骤之一就是确定影响管道事故因素的权重,各个管道风险因素在整个管道事故中所占的权重是不相同的。针对目前管道风险分析指数评分法基本假设之一（各因素的分值范围都是0～100分）,为了更加客观、准确、合理地反映各个风险因素对于管道事故的影响程度,提出并论述了依据层次分析法的数学逻辑性进行综合计算得出管道风险因素的权重,然后对评分法中各个因素的最高分值,根据其权重不同进行相应调整,从而增强评价者对风险因素的认识和评判能力,提高管道风险评价结果的准确性。     

A century of evolution of the accessibility concept

The concept of accessibility has acquired numerous meanings along multiple dimensions during the century of its evolution. This essay argues for the salience of two dimensions: application-based and definition-based. In its application, accessibility has incorporated positive and normative dimensions which have varied in prominence over time. In its definition, accessibility has varied between a mode of evaluation incorporating measured mobility and proximity, on the one hand, and a predefined market basket of urbanist improvements to transportation and land use systems, on the other. Advocates of the accessibility shift should emphasize both the measured approach to accessibility and accessibility’s normative side.     

Real-world gaseous and particle emissions of a Bi-fuel gasoline/CNG Euro 6 passenger car

The objective of the present study is the assessment of the environmental impact of a bivalent (bi-fuel) vehicle, running either on gasoline or compressed natural gas (CNG). To that aim, a Euro 6 passenger car was tested under various real-world driving conditions. In order to cover the full range of conventional powertrains currently in the market, the tests were also repeated on a Euro 6 diesel passenger car. Both cars were driven in two routes, the first complying with the regulation limits and the second going beyond them. Carbon monoxide (CO), nitrogen oxides (NO_x) and particle number (PN) emissions were recorded using a Portable Emissions Measurement System (PEMS). Apart from the aggregated emission levels, in g/km, the exact emission location along the route was also assessed. Natural gas proved beneficial for CO and PN emissions, the level of which always remained below the respective legislation limits. On the other hand, under the dynamic driving conditions with gasoline, the relevant limits were exceeded. Cold start, occurring at the beginning of the urban part, and motorway driving were identified as major contributors to total emissions, especially in gasoline mode. However, the application of natural gas was associated with a penalty in NO_x emissions, which were significantly increased as compared to gasoline. Local peaks within the urban part were identified in CNG mode. In any case, the diesel vehicle was by far the highest NO_x emitter.     

Seaport performance analysis using robust non-parametric efficiency estimators

Abstract

Seaport services have been developing year on year, playing an increasingly important role in the economy and the transportation markets of each country. This increases interest in measuring their performance. This paper evaluates the performance of a set of European seaports by means of robust non-parametric approaches. Using order-m and bootstrap procedures, the major problems of traditional data envelopment analysis and free disposal hull methods – concerning noise, presence of outliers and the ‘curse of dimensionality’ – are overcome. With this study considerable levels of inefficiency were found in the European seaports sector.     

Bicycle parking: a systematic review of scientific literature on parking behaviour,parking preferences,and their influence on cycling and travel behaviour

ABSTRACT

Cycling is experiencing a revival in many cities. Research has focused on the determinants of cycling – in particular the role of the built environment and road infrastructure. Bicycle parking has received little attention – even though bicycles are parked most of the time. This article reviews the scientific literature on bicycle parking and identifies existing gaps in research and knowledge. The review analyses 94 peer-reviewed papers identified through a search in Scopus and Web of Science, in December 2017. The annual number of papers increased 15-fold between 1995 and 2017. Overall, the level of evidence on the importance of bicycle parking is limited. The majority of studies are based on cross-sectional data with the presence of parking as a binary independent variable. Most studies focus on bicycle parking at public transport stops and at work places. Few studies report on bicycle parking throughout cities, and hardly any on parking at residential locations. Bicycle parking supply and quality appears to be a determinant of cycling for current and potential cyclists. Our findings can serve as input for an evidence-based debate on the role of bicycle parking. For practitioners, our research supports investment in bicycle parking, but acknowledges that a proper evaluation of such initiatives needs to be conducted to increase the level of evidence.     

Multilevel analysis of daily time use and time allocation to activity types accounting for complex covariance structures using correlated random effects

In this paper multilevel analysis is used to study individual choices of time allocation to maintenance, subsistence, leisure, and travel time exploiting the nested data hierarchy of households, persons, and occasions of measurement. The multilevel models in this paper examine the joint and multivariate correlation structure of four dependent variables in a cross-sectional and longitudinal way. In this way, observed and unobserved heterogeneity are estimated using random effects at the household, person, and temporal levels. In addition, random coefficients associated with explanatory variables are also estimated and correlated with these random effects. Using the wide spectrum of options offered by multilevel models to account for individual and group heterogeneity, complex interdependencies among individuals within their households, within themselves over time, and within themselves but across different indicators of behavior, are analyzed. Findings in this analysis include large variance contribution by each level considered, clear evidence of non-linear dynamic behavior in time-allocation, different trajectories of change in time allocation for each of the four dependent variables used, and lack of symmetry in change over time characterized by different trajectories in the longitudinal evolution of each dependent variable. In addition, the multivariate correlation structure among the four dependent variables is different at each of the three levels of analysis.     

从"神经末梢"到"国际枢纽"——十六大以来广西交通发展综述

文章总结了党的十六大以来广西交通发展取得的成绩,指出广西交通正在从"神经末梢"发展为"国际枢纽",为广西经济社会发展提供了重要支撑。     

Increasing urban tram system efficiency,with battery storage and electric vehicle charging

This paper examines the possible placement of Energy Storage Systems (ESS) on an urban tram system for the purpose of exploring potential increases in operating efficiency through the examination of different locations for battery energy storage. Further, the paper suggests the utilisation of Electric Vehicle (EV) batteries at existing Park and Ride (P&R) sites as a means of achieving additional energy storage at these locations. The study achieves this through MATLAB modelling utilising captured GPS data and publically available information. This study examines the scenario of uni-directional substations with no interconnection between the overhead catenary for both directions of travel, and discusses the trade-offs between ESS size and required current limits.The results show the savings in both energy and basic CO₂ emissions alongside the discussion of Return on Investment (RoI) that can be achieved through the potential installation of ESS at identified ideal locations along the tram network. Moreover, this may be extended to the use of EVs as stationary ESS sited at the existing P&R facilities. Further, the model may also be used to inform future infrastructure upgrades and potential improvements to air quality within urban environments.