西康铁路秦岭特长隧道I线出口段TBM施工

秦岭特长隧道是在我国铁路隧道中首次采用掘进机法(TBM)施工的隧道.I线出口段从1998年2月16日至1999年8月26日,共完成掘进5720.118m,平均月进度301.06m,平均日进度10.307m,最高月进度508.96m,最高日进度35.254m.文章分析了秦岭特长隧道I线出口段TBM施工的掘进进度以及掘进速度与围岩类别的关系,并在此基础上介绍了TBM通过不良地质地段的施工对策,为敞开式TBM在我国隧道工程中的应用提供了宝贵经验.     

广深港高速铁路狮子洋水下盾构隧道修建技术

从环保要求与可持续发展战略考虑,水下隧道必将是我国跨江越海交通工程的主要选择方式。广深港客运专线狮子洋隧道为我国首座水下铁路隧道,也是我国第一条特长水下隧道,其设计速度达350 km/h,该隧道为广深港高速铁路的关键性工程。针对该隧道的工程地质环境和采用的盾构法施工技术,特别是该隧道在我国首次采用的盾构对接方法施工,本文重点介绍了该隧道修建的有关设计与施工的技术,并提出了相应的措施。     

综合地质预报方法在铜锣山隧道施工涌水预报中的应用

在富水隧道施工过程中,常突发涌水、突泥等工程地质灾害,对施工安全危害极大。工程实践表明,单一的地质超前预报方法造成漏判、误判严重,难以确保隧道施工安全。文章结合铜锣山隧道工程地质条件,提出采用综合地质超前预报技术对铜锣山隧道施工涌水进行地质超前预报,充分发挥TRT法、瞬变电磁法和超前水平钻法技术的各自优势。工程应用效果表明,该种组合的综合地质超前预报技术为该隧道施工决策提供了有效的地质参考依据,在一定程度上避免了隧道涌水、突泥等地质灾害的发生。     

突破在大断层中心地带修建双线隧道施工的技术难关

宝兰复线新王家滩双线隧道位于天水—沈家河—三阳川大断裂地带中心位置上，其围岩设计为Ⅱ一Ⅳ类，是全线工期的控制工程。从开工之日起，就受到了各方人士的高度关注。经施工单位反复研究，决定进口采用长台阶法施工，出口采用超前大管棚法施工。为确保工期的实现，必须加快施工进度循环。当按计划进度向前掘70m以后，围岩地质呈现显著的变化，全是I、Ⅱ、Ⅲ类软弱、破碎、地下水丰富的围岩地质结构。给开挖、支护、衬砌等施工带来了很大的困难。为了突破这一技术难关，决定用CRD法在新王家滩双线隧道施工中通过地质断层坍方涌水的艰难地段，为宝兰复线天水至宝兰段开通运营创造条件。     

双层隧道土建结构设计关键技术探讨

双层隧道为大断面隧道工程,结构新颖,施工工艺较为复杂,目前国内采用新奥法设计施工的双层隧道工程成功案例较少,可借鉴经验不多.本文结合温州某在建城市主干道双层隧道工程,分别从设计技术标准的采用、横断面设计、隧道结构设计、洞口过渡段设计、施工方案各角度对双层隧道进行论述,相对于普通公路隧道工程来讲,具有一定的创新.希望通过本文的分析与总结,为今后类似的双层隧道设计提供一些借鉴.     

郑西客专高桥隧道下穿既有铁路设计与施工

郑西客专高桥隧道出口下穿既有南同蒲铁路段集成了特浅埋、大断面、新黄土、小角度下穿等技术难点,由于浅埋、新黄土隧道施工易发生较大变形甚至突然性塌方,为确保下穿段施工安全和既有线运营安全、同时保证隧道建设工期,通过技术经济比选,最终确定采用超前管棚+双层支护+台阶法方案。现场通过地表对既有线进行加固、洞内100 m长管棚超前支护和双层喷锚支护,以及仰拱快速封闭等技术手段,实现了采用台阶法安全、快速下穿通过既有铁路段的目的。文章介绍了方案比选情况和现场施工情况,对试验测试情况进行了总结分析,对大断面黄土隧道下穿既有铁路段采用双层支护台阶法的适用性进行了评价,并提出了其技术关键和相关注意事项,为类似工程提供了一种新的建设思路。     

梅岭关隧道水平岩层稳定性分析与施工技术

水平岩层是地下工程中经常遇到的一种岩体,具有明显的各向异性力学性质,其变形破坏特征表现得更为复杂.为了及时预防大跨度隧道穿越水平岩层施工过程中极易出现的平拱、拱顶离层破坏、拱顶弯折内鼓等危害现象,确定合理的支护方案,文章结合新建兰渝铁路梅岭关隧道,根据现场跟踪调查和试验,在对隧道地质特质和影响围岩稳定性因素等进行分析的基础上,提出针对性施工技术措施,并经施工实践证明,避免了隧道坍塌等恶性安全事件的发生,从而有效指导了隧道设计和施工.     

深圳水库流域污水截排隧道设计与施工

深圳水库流域污水截排工程主污水隧道全长7133 m,是涉及香港供水问题的一项重点工程,是全国首条城市排污隧道。隧道先后穿越水库、山岭、既有水渠、道路等。过沙湾河口段的隧道洞身穿越的各类风化岩层相互交错、覆土层薄(最小覆土仅2 m)、强透水条件,地质条件尤为复杂;过山岭段存在大量的富水断层,局部偏压。综合考虑了地质条件及周边环境,不同区段分别采用了盾构法、明挖法、矿山法、顶管法等。根据隧道防腐、排气及检修需要,对隧道分别进行内防腐涂装、排气井及检修洞设置。文章对各区段设计方法及施工难点及对策作了详细介绍,工程建成使用2年后的质量检查表明,该工程设计及施工是成功的。     

某偏压连拱隧道地质病害地震CT探测及病害处理

文章介绍了某高速公路偏压连拱隧道在衬砌结构发生严重破坏和隧道上方产生规模较大的山体开裂的情况下,所采取的病害处理措施.首先通过地震CT手段对该连拱隧道出现的工程地质病害进行探测;然后据此探测结果对该连拱隧道施工全过程进行动态施工模拟研究;最后分析导致该连拱隧道衬砌结构发生严重破坏的可能原因.结合现场病害调查结果,提出了相应的建议处理方案和施工过程中应注意的几个关键性问题.     

西气东输靖边至临汾段隧道工程的设计与施工

西气东输管道工程从靖边至临汾段共设计有12座山岭隧道,其中11座隧道穿越黄土地层,1座隧道穿越岩石地层.文章介绍了隧道的工程地质和水文地质概况以及设计原则和施工方法,总结出了天然气管道隧道工程的设计与施工特点.     

Bicycles in large cities in China

Bicycles are a main means of transport in China. This paper discusses several aspects of the current situation and future policy, including the production of bicycles, their possession and utilization in typical large cities, the reasons for their importance in communication, the advantages and problems of bicycle traffic, and two different opinions on solving the existing problems. The paper also deals with road design for bicycles and their regulation in China's cities.     

Travel choices in alcohol-related situations in Virginia

Transportation - Using survey data from 3004 respondents aged 21 and older in Northern Virginia, Richmond, and the Tidewater area, this paper identifies factors associated with respondents’...     

Parking policies in large cities in Germany

This article deals with highly motorized large West German cities of about 200,000 inhabitants and more, which usually provide reasonable public transport systems. Illegal parking with shares of about 40 to 50% of the total parking is widespread in the parking problem areas of those cities, especially in the inner-city residential and mixed-use areas. Parking spaces are demanded by residents, employees, customers and visitors, and by delivery and service traffic. The different characteristics of parking demands by different user groups are discussed. The total parking supply consists of public and private spaces. The share of private spaces is about 40 to 50% of the total parking spaces in German cities. The amount of car traffic generated by a parking space depends on parking duration and parking turnover, as well as on search traffic. So the change of a space from long-duration use of an employee to short-duration of customers — as often discussed in parking concepts — generates at least five-fold car traffic. The measurements and effects of parking control of public spaces as well as the parking regulations in zoning ordinances, restrictions on the construction of new private parking spaces and park-and-ride are discussed. Finally, a parking concept methodology — using the example of Frankfurt am Main — is discussed.     

Logistics opportunities in Asia and development in Taiwan

The economy in Asia is growing rapidly. As a consequence, transportation and communication technologies and the changing needs of customers and shippers have resulted in Asian and Taiwan's logistics being in transition. This paper discusses why logistics changes, and explores the opportunities for Asian logistics development. The issues of logistics perspectives of private sectors in Taiwan are then raised. Finally, logistics development in Taiwan is described.     

Changes in transport risk perception in urban populations in Norway from 2004 to 2013

Urban populations transport risk perception is interesting because it is associated with travel mode choices and use. This study investigates changes in transport-related risk constructs in the urban population in Norway in 2004 and 2013, and describes whether people perceive private or public to be associated with the highest risk. The results are based on self-completion questionnaire surveys conducted in two independent representative samples living in the same urban areas in 2004 (n?=?592) and 2013 (n?=?1035). Overall, the respondents perceived the risk as lower in 2013 than in 2004. For both time periods, people consistently assessed the risk constructs related to private motorized transportation as higher than corresponding risk in public transportation. The findings suggest that while transportation risk perception in urban populations may change over time, the pattern that private motorized transportation is associated with a higher perceived risk than public transportation remains stable.     

Role of transport in rural development in Africa

Rural Africa is starved of transport services. The transport routes run towards the export enclaves and the coast.

The political, social and developmental rural transport benefits are discussed. Rural transport will help (i) integrate the country and ease its governance; (ii) widen markets; (iii) induce increased agricultural output, through new technologies, reduced transport costs, etc. The transport cost savings should be passed on to rural firms and producers. The paper warns against their accruing only to middlemen — agricultural parastatals inclusive, thereby stifling the benefits to production. This could happen under some forms of pan‐territorial pricing. Negative aspects of road development, e.g. the substitution of local goods by imports, increased migration and noise, are noted.

The place and role of project appraisal in rural road planning is acknowledged. The broad‐based development packages approach associated with Integrated Rural Development Projects has, despite its attractions, some pitfalls. It favours well established villages and ignores distribution benefits within villages.

Project appraisal can be used to justify socially uneconomic transport developments. However, rural road investment projects with immediate negative returns are unlikely to be funded. Given clear priorities, short of elaborate cost/benefit analysis, obvious road investments choices can be made by the local community. Greater public accountability of transport planners and peoples’ participation in determining rural transport needs and priorities is emphasized. Increased rural road maintenance especially through self‐help schemes and increased use of traditional modes of transport, e.g. walking, animal and water transport, is recommended.     

Mapping minibuses in Maputo and Nairobi: engaging paratransit in transportation planning in African cities

ABSTRACT

Often called paratransit because of their flexible stops, schedules and routes, minibuses make up the bulk of public transport in African cities. Despite their ubiquity and importance, these systems are poorly understood by transportation planners who tend to focus on large-scale urban infrastructure projects such as highways, commuter rail or bus rapid transit systems. The assumption within much of this planning is that these minibus systems are barriers to change and will become at most secondary “feeder” buses within large-scale projects, but structured plans detailing this vision are lacking. This paper argues that frequent failure to collect data and value important paratransit systems as a critical part of transportation in their own right is deeply problematic from the point of view of equity, access and inclusive and effective planning. We ask whether the growing number of bottom up mapping projects of minibus systems can disrupt this status quo. By comparing two mapping projects, Digital Matatus in Nairobi and the Mapa Dos Chapas in Maputo, we find that inclusive, collaborative mapping can help render these minibuses more visible in planning and provoke more grounded and inclusive “planning conversations” on multi-modal integration, passenger information and minibus upgrading, all key but relatively marginalised aspects of creating accessible, low emission, high quality and safe public transport in African cities.     

Passenger rail in North America in the light of developments in Western Europe and Japan

Because of different geo‐demographic and economic conditions, the impact of the new passenger modes (road and air) on rail travel was much larger in North America than in Europe. In 1960s and 1970s, as the railway share of intercity traffic in North America shrunk to a negligible one or two percent, the passenger trains were abandoned by private railway companies and taken over by state organizations, which have continued to operate traditional trains and generate mounting losses. On the technology side, no attempts have been made to improve competitiveness of trains vis‐a‐vis automobiles and airplanes.

In Europe and Japan, the railways responded to the challenge by (i) upgrading the performance (speed) and comfort of traditional trains operating on existing tracks and (ii) developing trains which could, on short and intermediate range distances, compete successfully, in terms of speed and economy, with the road and air modes. The Japanese (Shinkansen trains) and French (TGV trains) experience clearly shows that trains operating on dedicated lines at average speeds of 150 to 200 km/hr provide a superior transportation service and economy on high‐traffic intercity routes of up to about 500 km length. In this paper the factors responsible for the present status of passenger rail in North America are analysed, the current policies in the U.S. and Canada are evaluated in the light of experience to date and developments abroad, and suggestions for a long‐term passenger rail policy are made. This includes examination of (i) the viability of continued subsidization of traditional train services, (ii) the viability of operation of faster trains on existing tracks, (iii) the scope for introduction of modern, fast trains on dedicated lines in high‐density, intercity corridors, (iv) the application of fast trains as access to major airports and integration of airports with fast intercity lines, and (v) the impact of energy (oil) consumption in transportation.

     

Heterogeneity among motorists in traffic-congested areas in southern California

Estimation of congestion costs, presumed to be one of the largest external costs of automobile travel, is typically based on a single value of time delay for motorists in metropolitan areas. However, the estimation may be wrong if the profiles of motorists are different at different times of day. This study uses a survival model to examine the demographic and socioeconomic profiles of motorists at different times of day at congested locations in southern California, by using on-road remote-sensing measurements and license plates images obtained in 2007 and 2008 by the California South Coast Air Quality Management District (SCAQMD). More than 80,000 vehicles were observed from fifteen selected study sites over fifteen days. Their plates, through anonymized registration records, revealed addresses at the census block group level, which have homogenous profiles by construction. Motorists’ profiles at different times of day display large variation, however, according to extended Cox model with a non-parametric baseline hazard, which is used to accommodate both the time-invariant and time-varying effects of the covariates. This study thus proposes a new approach to examine heterogeneity among motorists.     

美国煤浆体管道检测方法的新进展

从煤浆密度和浓度、流变参数和粒子带电量测量3个方面简要地总结了美国煤浆检测技术的新方法、新仪器的发展状况,分析了其发展特点。这将有助于促进国内煤炭浆体管道输送的发展。