SMW工法深基坑支护设计浅探

在众多深基坑围护方法中,SMW工法以其适用性强、围护成本低、施工周期短而倍受关注。结合SMW工法设计、施工的一个实例,对上海软土地基SMW工法深基坑支护设计的技术进行一些粗浅的探讨。     

SMW工法在南京地铁围护工程中的应用

SMW围护施工工法国外应用较多,目前在国内处于推广阶段.文章介绍了在南京地铁珠江路车站围护工程施工中SMW工法的应用情况,用工程实例说明了此工法在大型、超深基坑围护工程中应用的可行性.     

深基坑支护中的SMW工法

SMW工法是近年来兴起的一种新的深基坑围护形式,由于其具有无渗漏水、造价低等诸多优点,已得到越来越广泛的应用。文章结合工程实例,介绍SMW工法施工工艺及其操作要点,供同类型施工参考。     

SMW工法在浦东南路——张杨路下立交深基坑工程中的应用

结合上海某下立交的基坑工程设计与施工，分析SMW工法围护的基坑开挖引起的变形以及对周围环境的影响，为SMW工法这一集挡土、止水两大功能于一体的新型围护结构在上海软土地区的推广应用积累经验。     

地铁车站深基坑围护结构设计分析

为了优化地铁车站深基坑围护结构设计,保证结构的稳定性,首先阐述地铁深基坑支护施工现状,并在此基础上,对地铁车站深基坑围护设计施工中存在的问题进行分析,列举出当下常见的基坑围护结构中的常见围护形式。并针对具体问题,给出地铁车站深基坑围护施工的解决策略,并分别从设计专项、渗水措施、周边荷载、地连墙施工及加固施工等方面进行叙述。为今后相关技术人员研究地铁车站深基坑围护设计提供借鉴,通过对深基坑围护设计具体方法的探讨,进一步优化地铁车站深基坑围护建设,以期在一定程度上,规避地铁车站深基坑建设的风险及安全隐患。     

SMW工法在地铁静安寺站5号出入口下沉式广场基坑围护工程中的应用

在地铁静安寺站５号出入口下沉式广场基坑围护工程中,采用了ＳＭＷ工法。基坑开挖过程中严格遵循时空效应原则,做到分段、分层对称开挖,随挖随撑,使该种工法经受了盆式开挖掘施工方法的考验,围护效果良好。新颖的ＳＭＷ工法,正以其优越的社会,经济效益而逐渐走向大型的深基坑工程施工领域。     

深基坑围护结构中SMW工法桩施工工艺研究

为了提高深基坑围护结构施工质量,以广东省珠三角城际轨道交通琶洲支线工程为例,分析深基坑围护结构中SMW工法桩的特征,提出应用SMW工法桩施工工艺的施工方法,以期为同类型施工提供参考。     

淤泥质软土深基坑SMW工法桩围护结构施工技术研究

长江沿岸淤泥质土分布广泛、厚度大,承压水水位高,工程地质条件复杂,深基坑工程维护施工困难。文章结合南京青奥线梅子洲过江通道接线工程,对深基坑SWM三轴搅拌桩围护结构进行了系统研究;通过现场试桩与室内试验相结合,确定了水灰比、水泥用量、下钻速度、提升速度等主要施工工艺参数;并结合现场试验结果,研究分析了SMW工法桩围护结构的位移规律。工程实践表明,SMW工法桩围护结构在该工程地质条件下支护效果良好,对大型深基坑围护结构施工具有借鉴意义。     

SMW工法在上海国际会议中心地下车库围护设计中的应用

结合上海国际会议中心地下车库的设计,介绍基坑围护采用SMW工法的设计特点,阐述在不同环境条件下设计所采用的计算方法以及对地铁区间隧道的保护措施。     

超大型深基坑施工技术方案的探讨

上海世纪大都会基坑围护工程2—3地块为超大超深基坑,其中地铁6号线区间隧道穿越基坑,并将其分为两部分,在深基坑开挖下形成双面临空结构;基坑南侧又紧邻世纪大道枢纽站。从施工角度介绍和探讨了如何在基坑围护施工、地基加固和土方开挖等阶段有效地预测并控制其变形的方法和措施。     

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.     

Determinants of modal choice in freight transport

In the next few years, exciting developments in the field of freight transport are likely to occur. The Channel Tunnel will be perceived as giving railways much greater distance of operation, compared to the current train ferry to/from Great Britain. The further development of swap-body technology will allow easier modal transfer and the creation, in 1992, of a single market in Europe will transform the pattern of trade. All of these are likely to have significant impacts on modal choice, and hence modal split, in freight transport. Reappraisal by many firms of the modes of transport used is likely but will it result in a net transfer of freight from road to rail and, if so, to what extent? To answer such questions, an accurate and reliable method of predicting modal split is required. Research in the past has concentrated on the development of modal split models based on generalised costs. These fail to explain adequately the prevalence of road freight in the UK. From surveys of freight managers within industry, it is clear that models to date rely too heavily on the economic cost factor and too little on behavioural factors (Jeffs 1985). This paper derives from a recent study of freight transport modal choice from the standpoint of the transport decision-maker within the firm. It attempts to shed light on the actual parameters which should be incorporated into a modal split model. Many variables appear to exert an influence on modal choice decision-making process. However, it is possible to categorise them into six main groups, namely: customer-requirements; product-characteristics; company structure/organisation; government interventions; available transport facilities; and perceptions of the decision-maker him/herself. It is the interactions and inter-relationships between these which ultimately determine freight modal split. This study has shown that the relationship between the outcome of the transport decision process and the values of particular determinants of modal split is not straight-forward, due to the complexity and variety of interactions involved. Perhaps one of the main reasons for researchers' failure hitherto to develop a successful modal-split model has been the preoccupation with techniques that rely on the development of common metric (e.g. generalised cost), which has led to the exclusion of some important explanatory variables along quite different dimensions. Another important issue concerns the appropriate level of aggregation. In order not to reduce the explanatory power of the key variables, it is important to work at a disaggregate level, although this does make substantial demands on data. The use of factor analysis enables both the aggregation of information without loss of behavioural reality and the specification of variables in terms of a common metric. In conclusion, freight transport has usually been examined within too narrow a framework. It must be placed firmly within the context of the total industrial process. The demand for freight transport is directly influenced by the level, composition and geographical distribution of production and consumption activities. Freight flows are complex and so it is highly unlikely that a universal mode-choice model can ever be developed. Future research should, therefore, be directed towards developing partial models in response to specific needs of those involved in decision-taking in the freight sector.     

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。     

天然气站往复式压缩机活塞失效分析

针对天然气站往复式压缩机活塞的断裂事故,运用失效分析方法,开展了活塞断口扫描电镜分析、能谱和金相分析。根据断口形貌的电镜和金相观察结果,结合理论知识,分析确定了该活塞发生断裂事故的主要原因,即在特定工况下该活塞的材料缺陷是造成断裂的主要因素。     

中国城市道路规划方位性问题研究

文章结合中国的传统建筑文化理念和现代科学原理,从历史文化、能源节约、环境保护、房地产定价、交通安全等多方面分析研究了城市道路在规划和设计时所应遵从的定向规则。     

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.     

Predicting queue variability to enable analysis of overload risk

ABSTRACT

Predicting the risk of traffic demands and delays exceeding critical limits at road junctions, airports, hospitals, etc., requires knowing how both mean and variance of queue size vary over time. Microscopic simulation can explore variability but is computationally demanding and gives only sample results. A computationally efficient approximation to the mean is used in many modelling tools, but only empirical extensions for variance in particular situations have been available. The paper derives theoretical formulae for time-dependent and equilibrium variance, believed to be novel and to apply generally to queues covered by the Pollaczek–Khinchin mean formula, and offering possible structural insights. These are applied in an extended approximation giving mutually consistent mean and variance estimates with improved accuracy. Tests on oversaturated peak demand cases are compared with Markov probabilistic simulation, demonstrating accuracy (R^2?>?0.99) for typical random, priority-like (M/M/1) and traffic-signal-like (M/D/1) queues. Implications for risk analysis, planning and policy are considered.     

Planning guidelines for metro–bus interchanges by means of a pedestrian microsimulation model

The big paradigm for cities nowadays is to study the movement of pedestrians at the interface between metro and bus systems – metro–bus interchanges. When these interchanges are not well designed, walking is inefficient and can be unsafe for pedestrians. This paper analyses, by means of a pedestrian microsimulation model, metro–bus interchange spaces in order to propose planning guidelines for the city of Santiago de Chile. Specific objectives are (1) to identify the variables that provide efficiency and safety in those spaces; (2) to simulate different scenarios using the pedestrian simulation model LEGION; (3) to propose planning and design guidelines for pedestrian spaces at metro–bus interchanges; and (4) to contrast the recommendations in the recently opened terminal station on Line 1 of Metro de Santiago: Los Dominicos Station.     

生命大过天

文章介绍了广西壮族自治区公路管理局开展专项行动,治理以桥梁为重点的交通基础设施安全隐患的情况,针对在役桥梁、在建桥梁和农村公路桥梁存在的安全隐患提出了相应的治理措施。