不同成型方式下的水稳基层配合比设计研究

为了对水泥稳定碎石基层进行配合比设计研究,文章先通过级配理论确定最合理的集料掺配比例,并通过调节水泥用量及水掺量,分别采用重型击实法和振动击实法进行试件的成型。通过对不同成型方式下的基层进行力学性能和耐久性能分析表明,振动击实设计方法确定的配合比具有较好的力学性能和抗裂性能。     

二灰碎石基层冷再生施工技术应用

利用旧路面基层获取铣刨料,添加新鲜骨料、结合料后进行再生混合料级配组成及配合比设计。利用二灰比、集料含量与28d劈裂强度关系方程,对配合比进行验证。着重阐述了混合料拌和工艺及连续式拌和设备成品料仓的改进。在拌和、摊铺、压实、养生等工艺上对再生混合料的施工提出控制要点及质量控制措施。     

农村公路建筑废弃物基层施工技术

从材料、配合比、工艺流程等角度研究了农村公路建筑废弃物基层再生利用技术,包括建筑废弃物集料再生、基层配合比设计、拌和碾压等关键施工技术,有效解决了建筑废弃物变废为宝、节约资源、降低造价、保护环境等问题。     

振动搅拌对水泥稳定碎石基层均匀性的影响分析

文章依托广西某高速公路水泥稳定碎石基层实体工程,对比了振动搅拌与非振动搅拌状态下的水稳基层混合料的均匀性,并测试分析了水稳基层强度指标。结果表明:相比于非振动搅拌的水稳混合料,采用振动搅拌的水稳混合料均匀性变异系数和标准差更低,水泥分布和粗集料裹附更为均匀,水化反应更加充分,采用振动搅拌的水稳混合料颗粒合成级配更为稳定,振动拌和芯样相比非振动拌和芯样其强度提升近20%。     

振动搅拌对水泥稳定碎石路用性能的影响及效益分析

文章依托试验路工程应用,研究振动搅拌技术对水泥稳定碎石基层路用性能的影响,并进行效益分析。结果表明：振动搅拌水泥稳定碎石混合料的拌和效果、摊铺效果、碾压效果、芯样效果及强度指标均明显优于普通搅拌水泥稳定碎石混合料;相较于普通搅拌工艺,振动搅拌工艺可节约水泥剂量约0.5%;相比设备费用增长以及生产效率略微降低,振动搅拌技术经济效益显著,工程推广应用价值很大。     

基于纤维素改性的干粉砂浆配合比试验研究

文章为了掌握纤维素HPMC改性干粉砂浆的基本性能,优化配合比设计,改善拌和物的施工性能,采用常规的试验方法对HPMC改性砂浆的保水性能、力学抗压强度、抗折强度性能进行了综合研究,分析了HPMC、粉煤灰及灰砂比等变化对砂浆基本性能的影响。试验结果显示:(1)随HPMC用量的增加,砂浆分层度值和抗压强度值均呈下降趋势,在掺量0～0.2%范围内,分层度和抗压强度指标下降显著,在0.2%～0.35%范围内,二者的下降幅度显著减小;(2)随着粉煤灰掺量的增加,干粉砂浆的力学强度呈下降趋势,对7d早期强度的劣化效果更为显著,而对28d强度的劣化有所减弱;(3)随灰砂比的降低,砂浆的抗折强度、抗压强度均呈下降趋势,HPMC改性砂浆的保水性能优于常规砂浆,但在相同配合比条件下,HPMC改性砂浆的抗压强度、抗折强度值均低于基准砂浆的强度,且随着灰砂比的降低,抗压强度和抗折强度损失变化率均呈先增加后降低的变化趋势。总之,HPMC改性干粉砂浆具有优良的保水性能,显著改善了拌和物的施工和易性,综合分析确定在基准配合比相同条件下,优选灰砂比为1∶3,HPMC的掺加用量为水泥胶结料的0.1%,粉煤灰基准用量为10%。     

纤维混凝土路面施工技术探讨

纤维混凝土对提高路面强度及韧性具有重要的作用,越来越广泛的应用于公路路面工程中。鉴于此,对纤维混凝土中纤维材料的选择进行了探讨,并从配合比设计、钢纤维混凝土的拌和、运输及摊铺等方面分析了钢纤维混凝土的施工技术,可为相关施工提供参考。     

探讨水稳碎石基层施工控制的要点

在对水稳碎石基层的特性进行分析的基础上,文章从原材料、混合料配合比、拌和、摊铺、碾压以及施工缝处理等几个方面详细探讨了其施工的相关要点,对水稳碎石基层施工起到一定的参考作用。     

全掺磷石膏路面基层混合料组成设计与性能评价

磷石膏综合处置利用具有重要的生态和经济意义,目前将磷石膏应用于公路工程是磷石膏固废消解的重要技术途径之一,但仍存在利用效率低,长期性能难以评价等问题。本文提出了一种以磷石膏替代全部集料的全掺水泥磷石膏路面基层方案,首先通过室内对比试验确定了混合料拌和时间、成型方法、养生条件和压实度标准等参数,系统提出了水泥磷石膏路面基层材料的组成设计方法;以7d无侧限抗压强度为指标进行配合比试验,提出了水泥磷石膏基层材料推荐配合比（92%磷石膏+8%水泥+0.4%添加剂）;通过浸水、冻融循环和干缩试验,对全掺磷石膏基层的水稳定性和收缩特性进行了评价;最后通过全掺磷石膏基层足尺路面铺筑试验,验证了材料组成设计的合理性。     

道路基层内养生透水水泥混凝土性能研究

为了避免水分对路面基层的损坏,并增强路面基层抗裂能力,文章提出将透水水泥混凝土用于道路基层,采用内养生剂提升混凝土抗裂性,同时对内养生透水水泥混凝土配合比进行了设计,并对内养生透水水泥混凝土力学性能、抗裂性能、透水性能进行测试。结果表明：内养生透水水泥混凝土的7 d抗压强度、28 d抗压强度、28 d抗弯拉强度分达到10 MPa、 13 MPa、2.9 MPa,说明内养生剂能有效增强透水水泥混凝土的抗裂能力,且内养生透水水泥混凝土能满足高速公路基层强度等性能要求。     

Analysis of factors affecting the choice of route of pedestrians

Pedestrians as compared to vehicular traffic enjoy a high degree freedom of movement even in heavily congested areas. Consequently, there are more alternative links available to pedestrians between a given origin‐destination (O‐D) pair. This paper describes a study done by the University of Calgary to evaluate the factors affecting the choice of route on intra‐CBD trips or trips within the Central Business District (CBD).

An origin destination survey conducted in downtown Calgary, Alberta enabled the identification of the most significant factors influencing the choice. These factors were analyzed in relation to the physical characteristics of the location, personal characteristics of the trip maker and the type of the trip.

It appears that most people chose the shortest link and factors such as the level of congestion, safety or visual attractions were only secondary. This suggests that the length should be made a major consideration when planning and designing pedestrian links.     

注汽管道承压能力评估和实物试验验证

基于失效评估图技术对某注汽管道进行了承压能力评价,给出了管线在不同腐蚀壁厚情况下的极限承压能力和极限裂纹尺寸。并利用实物爆破试验验证了评价方法的安全性和有效性,通过对爆破断口进行宏观和微观分析,发现管段的开裂属于脆性开裂。     

实现多组态计量软件集中监控的可行性分析

天然气自动计量系统有多种组态软件,由于软件的不相通性,造成了计量系统数据采集的通用性差、数据传输与入库的时效性差、数据利用的可靠性低.结合各组态软件的实际情况,从设计上充分利用Oracle大数据处理能力以及Partition(分区表)的特性,实现历史数据的存储,应用WebService与COM+数据访问组件提供多层数据访问架构,采用OPC与DDE工业数据交换协议,实现了各站场计量数据的实时上传,为连续数据采集和实时监控提供了可能,节约了改造成本.     

Non-parametric analyses of efficiency of airports

This paper estimates the efficiencies and productivity changes of 12 international airports in the Asia-Pacific region based on data from 1998 to 2006. We apply stochastic frontier analysis (SFA) to compute efficiency estimates and use the Malmquist productivity index (MPI) to analyze productivity changes. We use the SFA model with a translog-type production function after testing the statistical hypotheses. According to the results of the SFA hypothesis tests, airports have experienced a technological regression; the deviations from the efficiency frontier are caused more by technical inefficiency than random noise. However, the inefficiency was found to decrease. The MPI reveals a declining trend resulting more from technological change than from efficiency change, with a decrease in inefficiency. Taken together, both the hypothesis tests and the MPI not only provide consistent conclusions, but also suggest that airports should concentrate on technological progress.     

波纹管应力分析研究进展

评述了波纹管应力理论研究方法的进展情况，围绕解析法、工程近似法和数值法，对波纹管理论研究中的一些主要成果作了较详细的回顾和总结，对各种研究方法作出了评价，展望了亟待解决的一些问题。     

埋地管道防腐保温层失效评价

明确埋地管道防腐保温层的技术评价标准,对埋地钢质管道的安全运行,延长管道使用寿命具有重要意义。为了对埋地管道防腐保温层做出有效评价,从间接检测与开挖检测2个方面,结合现场检测数据,提出了基于防腐保温层的电流衰减率、绝缘电阻率、质量状况与厚度的分级评价标准及基于4种评价指标的综合评判方法。工程实践表明,该评价标准对防腐保温层是否存在失效能做出有效判断。     

城市轨道交通杂散电流监测系统概述

介绍了城市轨道交通工程中杂散电流不同的监测系统的构成,分析了集中式、分散式和智能型等监测系统的配置和功能,以及智能型实时在线监测系统的重要意义,为轨道交通工程杂散电流监测系统的选择与应用提供参考。     

Preliminary results of an analysis of areas of influence in Shanghai

The main deficiency of most current modeling approaches to transportation can be identified as neglect of the integration of existing geographical knowledge in regard to the ex ante transport/land use modeling approaches, with its focus on territorial dynamics and theory development. This paper addresses this aspect of the problem by introducing a theoretical and methodological framework for the analysis of the interrelationship between land uses. The analysis attempts to determine to what extent the functional land use in a city can be considered an ordered pattern. The order sought does not rely on purely spatial configurations, but on the correlation of transportation and land use. The first section of this paper focuses on theoretical considerations. It stresses the fact that conventional approaches do not apply in the present context. It then suggests an alternative based on areas of influence and measured in terms of level of attractance of land uses. The second describes a procedure based on this alternative following the remarkable contribution of Hanjoul, Beguin and Thill. An application of this procedure to the analysis of Shanghai is then examined. Finally, an evaluation of the strategies for optimizing the interrelationship between land uses is presented. The paper concludes with a possible research agenda.     

输油管道中原油乳状液的流变性研究

原油乳状液的流变性是原油开采后在管道中输送的重要研究方面,为了更好地研究这一性质,采用电动搅拌机、偏光显微镜以及流变仪等仪器来测定不同含水率的原油乳状液在不同条件下的黏度,观测不同含水率的原油乳状液在偏光显微镜下的形态。并且分别对原油乳状液的黏度与含水率之间的关系以及与剪切速率之间的关系进行研究,初步确定了所测区块原油乳状液的转相点以及该区块原油乳状液的流变特性,为生产中的油气集输提供了理论依据。     

Direct analysis of the perceived importance of attributes of reliability of travel modes in urban travel

Reliability of travel modes was found to be the most important characteristic of transportation systems in several attitudinal investigations of individual travel behavior. This paper represents the first part of a research effort aimed at gaining a better understanding of the characteristics of reliability of transportation modes in urban travel. In this research, reliability characteristics are identified; their importance relative to each other is assessed, and an insight into possible structure of an objective reliability index is discussed. The research is based on perceived values of reliability, which were identified through a large attitudinal survey conducted in the Chicago metropolitan area.