水泥改良高液限土工程特性试验研究

针对高液限土含水率大、饱和度高、力学性能复杂等特点,通过室内试验研究了不同水泥剂量、含水率以及压实度条件下的水泥改良高液限土的工程特性。结果表明,合理的水泥含量及压实度的改良土无侧限抗压强度和水稳定性系数大;浸水作用会大幅度降低改良土的CBR值,压实度越低,浸水后越容易发生松散破坏,强度越低;合理的水泥用量、含水率以及压实度等能够有效提高改良土的回弹模量,改善路基抗变形能力和强度性能。     

空间圆管桁架混凝土组合梁受力性能试验研究

空间圆管桁架混凝土组合结构是一种新型组合结构,为了解其受力特点、破坏机理、变形能力、管桁架杆件的内力分布规律及界面相对滑移等,设计制作了2根弦杆未填充混凝土的不同混凝土翼板厚度的空间圆管桁架混凝土组合梁模型试件,采用三分点对称加载,对其进行受力性能试验研究。研究表明,在对称荷载作用下,组合梁的破坏形式为弯曲破坏,同时伴随有受拉腹杆节点焊缝的强度破坏;空间圆管桁架组合梁具有良好的承载能力和变形能力,相同荷载下,混凝土板厚的组合梁的承载能力高于板薄的组合梁;组合梁破坏时,其跨中挠度约为跨径的1/200;不考虑界面相对滑移的情况下,截面应变满足平截面假定;加载前期,支点截面界面相对滑移量大于 L/8截面,而加载后期,L/8截面界面相对滑移量大于支点截面;腹杆为非轴心受拉或受压杆件,且跨中位置腹杆的轴力较小,梁端位置腹杆的轴力较大。     

Modelling heavy vehicle car‐following behaviour in congested traffic conditions

This study develops a car‐following model in which heavy vehicle behaviour is predicted separately from passenger car. Heavy vehicles have different characteristics and manoeuvrability compared with passenger cars. These differences could create problems in freeway operations and safety under congested traffic conditions (level of service E and F) particularly when there is high proportion of heavy vehicles. With increasing numbers of heavy vehicles in the traffic stream, model estimates of the traffic flow could be degrades because existing car‐following models do not differentiate between these vehicles and passenger cars. This study highlighted some of the differences in car‐following behaviour of heavy vehicle and passenger drivers and developed a model considering heavy vehicles. In this model, the local linear model tree approach was used to incorporate human perceptual imperfections into a car‐following model. Three different real world data sets from a stretch of freeway in USA were used in this study. Two of them were used for the training and testing of the model, and one of them was used for evaluation purpose. The performance of the model was compared with a number of existing car‐following models. The results showed that the model, which considers the heavy vehicle type, could predict car‐following behaviour of drivers better than the existing models. Copyright © 2013 John Wiley & Sons, Ltd.     

The ‘Four Dimensions of Behaviour’ framework: a tool for characterising behaviours to help design better interventions

This paper sets out the rationale and structure of a tool for assisting policy-makers and practitioners to understand behavioural challenges and open up thinking on the design of effective ‘behaviour change’ interventions. The ‘Four Dimensions of Behaviour’ (4DB) framework is based on the theoretical and empirical research in a range of policy domains including transport and pro-environmental behaviour more generally. The 4DB framework characterises multifaceted behaviours along dimensions of actor, domain, durability and scope. Its application in workshop or structured settings opens up diverse and non-exclusive discussion on designing interventions to match salient behavioural characteristics. The use of the 4DB framework in the transport domain is demonstrated for travel behaviours of interest to policy-makers using examples of buying plug-in vehicles (PiVs), commuting by bicycle, eco-driving and making business trips by train.     

组合移动支架现浇连续箱梁施工特点与安全技术措施

移动支架法具有结构合理、材料用量省、不需预制场地、整体性好等诸多突出优点.结合实际工程,探讨了移动支架法施工过程中的安全技术措施,并进行了力学验算,可为相关工程提供参考.     

基于重复加载蠕变试验的沥青混合料高温稳定性能研究

为了研究车辙随温度和应力改变的变化规律,对AC-13、AC-16和AC-20三种不同级配沥青混合料,在三种温度下进行重复加载蠕变试验,提取多种反映沥青混合料高温变形性能的力学参数,并进一步分析了这些参数在不同温度水平下的变化规律.研究结果表明,随着温度的增加,劲度模量、流动次数和斜率表现出一定的规律性,而永久变形没有明显的规律性;加载应力为0.7MPa、温度为60℃时,劲度模量、流动次数和斜率对于三种不同的混合料区分度最大.     

聚合物水泥混凝土性能研究

采用外掺聚合物对普通混凝土进行改性,基于试验研究聚合物水泥混凝土的性能.结果表明,聚合物水泥混凝土较普通水泥混凝土具有更好的力学性能和耐久性能,值得在施工中应用与推广.     

填石路基码砌边坡厚度研究

码砌是填石路基较为常用的边坡形式,目前设计规范对于码砌厚度要求偏高,在填石路基实际施工中往往达不到要求。本文采用力学计算与有限元模拟分析相结合的方法对路堤稳定性进行研究,结合调研已通车多年的任寨路、水南路及刚通车的六宜路等路段填石路堤码砌边坡薄层码砌的使用情况,提出填填石路堤填边坡进行50 cm的薄层码砌即可满足稳定性要求。     

高速公路机电工程相关界面的合理划分

加强机电工程的设计及管理不仅能保证工程质量,而且能够降低工程造价,提高施工效率。合理划分高速公路机电工程相关界面,能有效确保和提高高速公路机电设施在公路运营和管理中的作用与地位。     

试论高速公路机电工程的施工管理

从高速公路机电工程施工管理的界面跟踪、联合设计、施工图设计、设备调试安装的质量检测和试运行5个阶段,系统地分析了每个阶段的工作重点,为建设管理部门搞好施工管理提供借鉴。