共查询到20条相似文献,搜索用时 62 毫秒
1.
从物理化学、施工两方面分析盐渍土腐蚀性介质环境对桥涵混凝土结构物的腐蚀原因和机理,提出在设计和施工中采取的防腐措施,以保证桥涵混凝土结构物的安全和耐久性,延长其使用寿命。 相似文献
2.
桥涵混凝土裂缝普遍存在,一定程度上影响了桥涵的抗渗性和耐久性等使用性能。结合裂缝成因的分析,提出混凝土裂缝的防治及处理措施,与同行共同交流讨论。 相似文献
3.
4.
由于桥涵跳车现象已成为公路使用过程中普遍存在的质量通病.解决桥涵跳车这一质量隐患,对延长桥涵的使用寿命,提高行车的安全性和舒适性也具有十分重要的现实意义.从地质、路基填料、设计和施工等方面分析了桥涵跳车产生的原因,并从设计方面,施工管理与控制,监理层面入手进行防治措施的探讨. 相似文献
5.
在多年冻土地区,桥梁一般采用钻孔灌注桩基础.但由于地基的冻融作用影响,会产生各种工程病害,包括在钻孔灌注桩施工过程当中.选用合适钻机减少施工扰动,使用低温或负温水泥混凝土确保多年冻土地区桩基质量,且密切注意回冻时间长短,保证后续工序施工质量. 相似文献
6.
7.
察尔汗盐湖地区盐盖缺失地段地下水位高,地基土质不良(粉土),氯盐、硫酸盐含量高。修建混凝土构造物面临基础处理难、防腐难等问题。本文结合大察高速公路桥涵施工实际,就组合式钢波纹管在该地区施工的优点进行了阐述。 相似文献
8.
9.
根据桥涵施工手册,结合工程实践及多年的施工经验,就桥梁钻孔灌注桩水下混凝土施工事故的预防及处理进行论述。 相似文献
10.
11.
12.
Recent years have shown a rising popularity of the concept of resilience—both theoretically and empirically—in complex systems analysis. There is also a rising literature on resilience in the transport and spatial-economic field. The pluriform interpretation of resilience (e.g., engineering vs. ecological resilience) is related to methodological differences (e.g., stability in dynamics vs. evolutionary adaptivity). But in all cases the fundamental question is whether a complex system that is subjected to an external shock is able to recover, and if so, to which extent. The present paper [Based on presentation from cluster 6 (Accessibility) of the Nectar 2015 conference in Ann Arbour, USA.] aims to add a new dimension to resilience analysis in spatial systems, by addressing in particular the relationship between spatial accessibility at a municipality level and the resilience outcomes of the spatial system concerned. It does so by investigating to which extent accessibility of Swedish and Dutch municipalities has mitigated the local shock absorption from the recent economic recession. In our study the shock absorption capacity of municipal accessibility is estimated by analysing the relevant resilience indicators for the period concerned. In this context, conventional resilience indicators based on either multivariate complex data (in particular, the Foster Resilience Capacity Index) or employment data (in particular, the Martin Resilience-Employment Index) are confronted with spatial connectivity data based on local accessibility measures, so that geographical mobility may be regarded as one of the shock-mitigating factors. The empirical analysis is carried out for two countries which have both proven to be rather shock-resistant during the recent economic crisis, viz. Sweden and The Netherlands. Clearly, the geographical structure of these countries forms a sharp mutual contrast, viz. a spatially dispersed economy with a few distinct urban concentrations versus a spatially dense economy with one major metropolitan centre (the Randstad), respectively. Our experiments are carried out for the 290 municipalities in Sweden and 40 COROPs in The Netherlands. Our research findings show relevant and new insights into differences in the local recovery potential in Sweden and The Netherlands. 相似文献
13.
14.
15.
In modern cities, a rapid increase of motorcycles and other types of Powered Two-Wheelers (PTWs) is observed as an answer to long commuting in traffic jams and complex urban navigation. Such increasing penetration rate of PTWs creates mixed traffic flow conditions with unique characteristics that are not well understood at present. Our objective is to develop an analytical traffic flow model that reflects the mutual impacts of PTWs and Cars. Unlike cars, PTWs filter between cars, have unique dynamics, and do not respect lane discipline, therefore requiring a different modeling approach than traditional “Passenger Car Equivalent” or “Follow the Leader”. Instead, this work follows an approach that models the flow of PTWs similarly to a fluid in a porous medium, where PTWs “percolate” between cars depending on the gap between them.Our contributions are as follows: (I) a characterization of the distribution of the spacing between vehicles by the densities of PTWs and cars; (II) a definition of the equilibrium speed of each class as a function of the densities of PTWs and cars; (III) a mathematical analysis of the model’s properties (IV) an impact analysis of the gradual penetration of PTWs on cars and on heterogeneous traffic flow characteristics.The proposed model could contribute as an enabler for ‘PTW-aware’ future Cooperative Intelligent Transport Systems technologies and traffic regulations. 相似文献
16.
17.
The bicycle is often understood as a disjointed ‘feeder’ mode that provides access to public transport. We argue that combined use of the bicycle and public transport should be understood in a broader perspective, especially where bicycles link to higher speed and higher capacity public transport, such as the train. Cycling and public transport can have a symbiotic relationship forming a hybrid, distinct transport mode, which should be reflected in transport planning. The bicycle is as a way to soften the rigid nature of public transport and thus accommodate diverse individual travel needs and situations. Public transport can be seen as a means to dramatically extend cycling’s speed and spatial reach. We combine a system perspective with conceptual analysis to explore how, why and when this reconsideration is important. We use the Netherlands as illustrative case because of the relative maturity of its bicycle–train connections. The case shows that the synergy between rather opposite yet highly complementary aspects, high speed of the train, high accessibility of the bicycle and flexibility in combining both sub-modes, are the fundamental characteristics to understand the functioning of this system in a wider spatial context. In our conclusion we propose a research agenda, to further explore the relevance of this system for land-use and transport planning and distil wider implications for the international debate. 相似文献
18.
《综合运输》2020,(1)
智能系统的广泛使用,带来了移动支付的普及。公交支付在传统IC卡和现金支付的基础上,加入了云闪付和二维码支付。为探究移动支付对公交支付效率的影响,基于杭州市公交发展现状,制定了公交支付情况的调查方案。通过对所选10、93、97公交线路的早、晚高峰和平峰的三天实地调查,采集视频数据并使用SPSS进行定量统计分析,发现公交乘客刷卡占62%、二维码占27%、云闪付占6%、现金占5%。当乘客提前做好准备时,刷卡支付时间为1.29 s,低于云闪付的1.42 s和二维码的1.65 s,而未准备好时用时分别为6.74 s、10.94 s、8.54 s。通过相关性和多元线性回归分析得出"提前拿卡"、"上车掏卡"、"提前开二维码"和"上车开二维码"四种支付方式对公交停留时间延长的影响最大。 相似文献
20.
开展水土流失监测是水土保持监管的重要手段。文章以广西沿海高速公路改扩建工程一期工程水土保持监测实践为例,分析了工程建设水土流失特点,介绍了水土保持监测技术和方法,并通过对工程实例监测结果的分析评价,提出了水土保持监测工作中易出现的问题及相应的解决方案。 相似文献