公路路线设计中存在的问题及设计要点研究

在公路工程设计中,路线是重要设计内容。为保证公路的行车安全与行车质量,设计人员需科学、合理地设计公路路线。设计人员在公路路线设计过程中,应严格遵守相关公路设计规范要求,了解、掌握公路工程现场实际情况,综合分析各种路线设计影响因素,对公路路线平面、纵断面、视距、生态环保等方面进行合理化设计。通过对公路路线设计中存在的问题及设计要点进行深入研究,为同类工程设计提供参考。     

山区低等级公路设计困难及设计要点分析

为进一步优化山区低等级公路设计,对山区低等级公路设计的特点、设计工作中存在的困难以及设计要点进行研究,提出优化线路设计、路基设计、桥涵设计的要点,旨在为相关人员提供一定参考。     

小交通量农村公路设计过程研究

为提高小交通量农村公路设计的合理性,对路线设计、路基路面设计、安全生命防护工程设计过程进行探索,明确设计要求标准、设计注意事项,以供设计人员参考。     

公路路面构成形式设计研究

为了提高公路路面的设计水平,以江西某拟建工程项目为例,探讨路面构成新式设计要点,阐述该拟建工程项目基本资料,从路面结构层设计、路基结构层设计多方面阐述路面构成设计主要内容,提出设计中的注意事项,为后续工程项目建设提供理论参考。     

公路路线纵断面设计方法分析

为了优化公路路线纵断面设计,主要对公路路线纵断面设计方法进行探讨。首先阐述纵断面设计的相关指标,其次在明确公路线路纵断面设计原则的同时,详细探讨公路线路纵断面设计的主要方法,并且对设计优化措施进行探究,以期为同类型公路路线设计工作提供参考。     

基于总压头相等的管道设计

输油管道有静压头相等设计和总压头相等设计两种设计理念。通过图形对比,直观展现了总压头相等设计相对于静压头相等设计的优势,通过假定地形参数和设计参数,运用管道设计计算公式和计算流程,计算静压头相等和总压头相等这两种管道设计理念的管线投资和抗风险能力,结果表明总压头相等设计理念在钢材使用与固定资产投资上具有优势,表明了这种设计的管道运行安全系数高、运行操作简单、可操作范围大、抗风险能力强等优点。     

公路设计新理念

针对公路建设现存的主要问题,从设计结合自然、公路设计灵活性、公路宽容性设计、公路总体景观设计等方面,分析、阐述设计新理念的内涵,来拓宽设计人员灵活运用新理念的思路。     

如何加强公路水泥稳定砂砾基层施工

当前生态节约型的公路设计已经成为公路设计的重要方向之一,本文通过结合S248线呼图壁-芳草湖公路设计实例,以生态节约型的设计理念来进行该公路整体设计,系统地总结出公路的具体设计实施,为同类工程提供参考借鉴。     

公路弃土场排水系统设计方案研究及具体案例分析

为提高公路弃土场排水系统设计水平,对边坡排水系统设计的重要性及弃土场排水系统特点进行分析,结合实际经验提出弃土场排水系统设计要点,针对某公路弃土场排水系统具体设计案例的方案研究过程及具体设计方案进行阐述与分析,详细介绍设计要点的具体技术措施,为公路边坡及弃土场的排水系统设计提供设计经验及案例借鉴。     

浅析现代桥梁耐久性设计的新理念

文章以现代桥梁的耐久性设计为研究对象,结合桥梁耐久性设计理念发展历程,从内力计算、全寿命设计、规范化设计三个方面阐述了现代桥梁耐久性设计的新理念,为今后桥梁的耐久性设计提供相应参考经验。     

公路网规划环境影响评价内容、程序和方法体系研究

在总结研究目前国内已有公路网规划环境影响评价工作的基础上,根据规划环境评价的目标要求和公路网规划的实际,提出了包括内容、程序和方法等的公路网规划环境影响评价体系,提高现有公路网规划环境评价能力和未来公路网规划环境评价质量。     

Walking,cycling and the urban form: A Heckman selection model of active travel mode and distance by young adolescents

Physical inactivity of children and adolescents is a major public health challenge of the modern era but, when adequately promoted and nurtured, active travel offers immediate health benefits and forms future sustainable and healthy travel habits. This study explores jointly the choice and the extent of active travel of young adolescents while considering walking and cycling as distinct travel forms, controlling for objective urban form measures, and taking both a “street-buffer” looking at the immediate home surroundings and a “transport-zone” looking at wider neighborhoods. A Heckman selection model represents the distance covered while cycling (walking) given the mode choice being bicycle (walk) for a representative sample of 10–15 year-olds from the Capital Region of Denmark extracted from the Danish national travel survey. Results illustrate the necessity of different urban environments for walking and cycling, as the former relates to “street-buffer” urban form measures and the latter also to “transport-zone ” ones. Results also show that lessening the amount and the density of car traffic, diminishing the movement of heavy vehicles in local streets, reducing the conflict points with the density of intersections, and intervening on crash frequency and severity, would increase the probability and the amount of active travel by young adolescents. Last, results indicate that zones in rural areas and at a higher percentage of immigrants are likely to have lower probability and amount of active travel by young adolescents.     

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。     

分形理论在油气储运工程中的应用综述

介绍了分形理论的基本思想。综述了分形理论在油气储运工程中多个领域（如油气水多相流流型识别、管道腐蚀评定、管道粗糙表面的分形模拟、管道疲劳裂纹分形研究等方面）的应用和研究成果,并提出了需要深入研究和完善的5个方面。     

A new approach for modeling of Fundamental Diagrams

According to the intra-vehicle interaction, a traffic flow can generally be divided into three homogeneous states (1) that of free driving, (2) that of bunched driving, and (3) that of standing. The parameter describing the state of free driving is the desired speed, for the state of bunching it is the intra-vehicle gaps (time headway) within the convoy and the mean speed of the convoy, and for the state of standing it is the maximum jam density. These are the most essential parameters which do not depend on the actual traffic situation.This paper introduces a new model which considers the Fundamental Diagram (equilibrium speed–flow–density relationship) as a function of the homogeneous states. All traffic situations in reality can be considered as combinations of the homogeneous states and therefore can be described by the essential parameters mentioned above. The non-congested (fluid) traffic is a combination (superposition) of the states of free driving and bunched driving, the congested (jam, stop, and go) traffic is a combination of the states of bunched driving (go) and standing (stop). The contribution of the traffic states within the differently congested traffic situations can then be easily obtained from the queuing and probability theory. As a result, Fundamental Diagram in all equilibrium traffic situations is derived as simple functions of the essential parameters.According to the new model the capacity of freeways and rural highways can be determined by measuring the essential parameters. This is much easier than measuring the capacity directly.Furthermore, the probabilities of the various traffic states can be obtained from the new model. This leads to new possibilities in real-time controlling and telematics.The new model is verified by comprehensive measurements carried out on freeways and rural highways in Germany.     

The role of public authorities

Advances in information technology and telecommunications are opening up the possibility of transforming the capture, application and dissemination of information on transport operations and road traffic, at the same time as growing congestion makes accurate and timely information more valuable than ever to users and managers. Because of open access to road networks, public authorities are bound to intervene in the field of travel information: in the provision of infrastructure, the handling of the information, the licensing of services, and the regulation of users affecting safety or social well-being. The paper discusses these rôles and the levels at which they may be exercised, with particular reference to standardisation issues in Europe and internationally.     

国外铁路运营安全效益评价现状及启示

铁路运输在国民经济运行中发挥着重要作用,各国铁路公司都非常重视对铁路运营、安全、效益的管理及评价。国外铁路经过两个世纪的发展,积累了丰富经验,通过分析美国、日本、欧洲等国家和地区的普速、高速铁路,在运营效率评价、运营安全评价、服务质量评价、经营效益评价、安全保障法律法规建设和第三方评价机构发展等方面的现状,从客户服务质量评价、安全评价标准体系建立、效率效益导向的经营效益评价机制建设、第三方专业评价机构发展等维度,总结对我国高速铁路运营安全效益评价的经验借鉴及启示。     

Factors affecting the use of bus and rail services in a deregulated environment

In 1987, the NSW Government commenced deregulation of the long-distance bus industry in NSW. This immediately led to greater inter-modal competition and contestability within the context of changing passenger markets.This study utilises categorical data analysis methods to examine the emerging passenger markets of inter-modal competitors (bus and rail) and to assess the relative importance of socioeconomic and travel related variables which affect the use of bus and rail services along the high volume Sydney-Canberra and Sydney-North Coast corridors.Conclusions from the study indicate varied passenger markets within a relatively new contestable environment which are mode and corridor specific. Results are indicative of the need for competitors to develop marketing strategies conducive to the demands of the travelling public in order to enhance viability and commercial opportunities.     

Emergence of resilience as a framework for state Departments of Transportation (DOTs) in the United States

State Departments of Transportation (DOTs) in the United States are responsible for a large portfolio of transportation modes and services, including passenger and freight systems. These responsibilities include operations under routine conditions and during incidents and events that result from various natural and human-caused hazards. During unexpected events, disruptions and reductions in service result in requiring the reallocation and reassignment of personnel, modal, and economic resources. To better prevent and respond to the effects of service disruptions, the concept of resilience has emerged as an important framework, within which, DOTs across the United States are using to plan for the occurrence of threats. In this paper, the key findings of recent reviews of literature and practice related to resilience among state DOTs in the United States are summarized. The review effort focused on a range of risks faced by transportation agencies including climate change, terrorism, cyber-attacks, and aging infrastructure and the ways in which DOTs are confronting them in practice. The topics of this paper range from the fundamental, including definitions of transportation resilience; to the more complex such as examinations of risk, vulnerability and threats; to the most sophisticated topics including administrative-level efforts to conceptualize evolving transportation planning and policies within a resilience framework.