隧道施工中塌方的预防和处理

通过分析隧道施工产生塌方的原因,详细介绍了隧道施工塌方的预防、塌方出现的前兆以及塌方的处理,为今后隧道施工塌方的预防和处理提供参考.     

护拱法处理隧道塌方技术应用

隧道施工中塌方是常见的事故,塌方处理方案的关键是要安全、合理、经济.文章通过财神梁隧道塌方处理实例,从塌方原因分析、处理方案、变形监测等方面浅述了护拱法处理隧道塌方的施工技术.     

隧道贯通段塌方处理施工技术

文章通过公山隧道贯通段塌方处理技术的实例,从大断面隧道贯通段塌方的原因分析,介绍了隧道塌方的处理方案、施工工序等施工技术。由于本次隧道贯通段塌方的处理采取厂有效方案,保证了施工安全,处理过程中没有出现二次塌方和掉块现象,围岩和结构处于稳定状态,达到了预期的"安全、稳妥、保质、经济"的目的。其成果可供类似隧道的塌方处理参考、借鉴。     

王家岭双连拱隧道右线塌方处理

文章结合宜万铁路王家岭隧道双连拱施工与右线塌方处理方案,分析了隧道塌方的原因,着重介绍了隧道塌方处理措施及施工中的关键环节。     

浅析下沙隧道塌方处理方案

隧道施工中常出现塌方突发情况,如处理不当,在后续施工中可能导致较大的经济损失甚至人员伤亡。本文紧密结合下沙隧道施工中突发塌方病害实例,分析塌方原因,介绍隧道塌方后的初期处理到全部安全顺利通过塌方段的施工方案,以供对类似的隧道塌方处理有所借鉴。     

浅谈隧道穿越岩性分界面石质塌方处理措施

由于地质构造作用以及风化作用,隧道多存在地质条件复杂地段。当隧道穿越岩性分界面,处理不到位很容易导致隧道塌方,给隧道施工带来安全质量隐患。文章以靖西至龙邦高速公路乐村隧道穿越岩性分界面导致大体积塌方为例,介绍了隧道区地质情况和塌方情况,分析了塌方原因,提出了利用管棚并配合超前注浆小导管的支护处理方法,并阐述了塌方处理效果。     

土胎法在隧道塌方中的应用

针对隧道施工中常遇到的塌方事故,分析其产生的原因,并以永武高速公路龙井隧道塌方处理方案为例,重点介绍"土胎法"的应用。该法对处理地下水丰富、破碎的煤层地质围岩的隧道塌方有着操作方便、经济安全等优点,可为同类隧道塌方处理提供借鉴参考。     

何家坡隧道右洞塌方处理

本文结合何家坡隧道隧道右洞发生的塌方情况,分析了隧道塌方的处理方案,并对处理后围岩的稳定性进行了计算分析,分析结果可供同类工程参考.     

长导管穿越和CRD结合法在隧道塌方处理中的应用

文章在介绍常用隧道塌方处理方法的基础上,针对贵州厦蓉高速公路AT20合同段滚玉隧道的塌方情况及其产生原因,提出了长导管穿越和CRD结合的塌方处理方案,并阐述了方案的具体实施步骤及要点,探讨了方案的处理效果。     

长短大管棚法处理隧道塌方施工技术

文章以重庆开县龙安隧道为例,分析了该隧道塌方的原因,提出了长短大管棚处置方案,并详细阐述了长短大管棚法处理隧道塌方的施工技术,指出了施工注意事项,评述了采用该方法进行隧道塌方处置的效果。     

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.     

The Impact of Container Type Diversification on Regional British Port Development Strategies

Abstract

Despite a concentration of container traffic in the southeast of the UK over the last few decades, regional ports are attempting new development strategies to capture or retain specific traffic segments. These include intra-European short-sea traffic and a potentially increasing feeder market. These trends are reflected in the movement of different container types, which result in a number of planning challenges related to changing infrastructural and operational requirements. This paper uses highly disaggregated data on container type movements to address three issues that can inform these planning challenges. First, the imbalance of trade resulting in empty container repositioning; second, the requirement for gauge-cleared rail routes to cater for the increasing proportion of high-cube containers; and third, the specialisation of European short-sea traffic at secondary UK ports. The results reveal the disproportionate repositioning of empty containers at Scottish ports and the importance of 45?ft, high-cube and pallet-wide containers at regional ports, highlighting their focus on intra-European short-sea traffic and raising difficulties relating to their lower quality of landside infrastructure (particularly rail) in comparison to the large south-eastern ports. The potential repercussions on hinterland infrastructure development raise questions about both public and private sector responses to regional port development.     

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.     

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。     

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。