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751.
高掺量粉煤灰对混凝土的耐久性作用研究 总被引:1,自引:0,他引:1
高掺量粉煤灰混凝土作为一种新型材料,具有自身独特的优越性。通过对高掺量粉煤灰混凝土的抗侵蚀性能、抗冻性、抗气渗透性与抗水渗透性、抗硫酸盐性这些耐久性能进行研究,并与普通混凝土进行对比分析,研究结果表明高掺量粉煤灰可以显著改善混凝土的耐久性能。 相似文献
752.
高速公路改扩建边坡工程的稳定性数值分析 总被引:1,自引:0,他引:1
针对某高速公路改扩建过程中对边坡工程的二次开挖卸荷的稳定性问题进行分析,采用有限元软件midas/gts对边坡的开挖支护过程进行模拟,得出了开挖边坡过程中的应力场变化规律,开挖同时应对边坡及时支护。并求得了支护后的边坡安全系数。 相似文献
753.
根据广西桂柳高速公路管理处日常养护调查情况,选择柳州至王灵高速公路中三段脱空比较严重路段作为试验路段,采用板底压浆方式进行处治,从原材料质量、压浆材料配合比、施工工艺以及施工质量检测等多个环节加以控制。通过板底压浆效果评定指标可以得出,压浆前、后路面板的传荷系数由68.6%增大至80.3%,脱空率由42.6%减少至13.3%,压浆效果良好,对处治板底脱空具有很好的应用。 相似文献
754.
进行大体积混凝土施工时必须根据混凝土水化热的具体情况,配备相应的监控系统—混凝土温度测试系统,对大体积混凝土凝固过程中的水化热进行实时温度检测,并对凝固过程进行全程检测和控制,采取相应的控制措施。 相似文献
755.
钢纤维混凝土在京福路K30+924通道桥桥面铺装抢修工程中的应用表明:钢纤维混凝土可以发挥良好的抗拉、抗弯、抗裂等性能,可改善桥面铺装的使用性能,延长桥面铺装使用寿命,缩短施工工期,是重交通量路段桥面铺装局部抢修最佳方案之一。 相似文献
756.
757.
三门海特大桥复杂的天然条件相对于主墩的深水基础施工而言相当恶劣,通过对高桩承台三个方案的优化比选,确定了承台采用钢吊箱施工方案,并详细介绍了水中临设、深水桩基、钢吊箱施工的方法,最后对深水基础施工进行了系统总结。 相似文献
758.
This paper looks at the first and second best jointly optimal toll and road capacity investment problems from both policy
and technical oriented perspectives. On the technical side, the paper investigates the applicability of the constraint cutting
algorithm for solving the second best problem under elastic demand which is formulated as a bilevel programming problem. The
approach is shown to perform well despite several problems encountered by our previous work in Shepherd and Sumalee (Netw.
Spat. Econ., 4(2): 161–179, 2004). The paper then applies the algorithm to a small sized network to investigate the policy implications of the first and second
best cases. This policy analysis demonstrates that the joint first best structure is to invest in the most direct routes while
reducing capacities elsewhere. Whilst unrealistic this acts as a useful benchmark. The results also show that certain second
best policies can achieve a high proportion of the first best benefits while in general generating a revenue surplus. We also
show that unless costs of capacity are known to be low then second best tolls will be affected and so should be analysed in
conjunction with investments in the network.
Andrew Koh Prior to joining the Institute for Transport Studies in December 2005, Andrew was employed for number of years as a consultant in highway assignment modelling. He is an economist with wide ranging research interests in transport economics as well as evolutionary computation heuristics such as genetic algorithms, particle swarm optimisation and differential evolution. Simon Shepherd At the Institute for Transport Studies since 1989, he gained his doctorate in 1994 applying state-space methods to the problem of traffic responsive signal control in over-saturated conditions. His expertise lies in modelling and policy optimisation ranging from detailed simulation models through assignment to strategic land use transport models. Recently he has focussed on optimisation of road user charging schemes and is currently working on optimal cordon design and system dynamics approaches to strategic modelling. Agachai Sumalee Agachai is currently an Assistant Professor at Department of Civil and Structural Engineering, Hong Kong Polytechnic University (). He obtained a Ph.D degree with the thesis entitled “Optimal Road Pricing Scheme Design” at Leeds University in 2004. His research areas cover transport network modeling and optimization, stochastic network modeling, network reliability analysis, and road pricing. Agachai is currently an associate editor of Networks and Spatial Economics. 相似文献
Agachai SumaleeEmail: |
Andrew Koh Prior to joining the Institute for Transport Studies in December 2005, Andrew was employed for number of years as a consultant in highway assignment modelling. He is an economist with wide ranging research interests in transport economics as well as evolutionary computation heuristics such as genetic algorithms, particle swarm optimisation and differential evolution. Simon Shepherd At the Institute for Transport Studies since 1989, he gained his doctorate in 1994 applying state-space methods to the problem of traffic responsive signal control in over-saturated conditions. His expertise lies in modelling and policy optimisation ranging from detailed simulation models through assignment to strategic land use transport models. Recently he has focussed on optimisation of road user charging schemes and is currently working on optimal cordon design and system dynamics approaches to strategic modelling. Agachai Sumalee Agachai is currently an Assistant Professor at Department of Civil and Structural Engineering, Hong Kong Polytechnic University (). He obtained a Ph.D degree with the thesis entitled “Optimal Road Pricing Scheme Design” at Leeds University in 2004. His research areas cover transport network modeling and optimization, stochastic network modeling, network reliability analysis, and road pricing. Agachai is currently an associate editor of Networks and Spatial Economics. 相似文献
759.
Bi Yu Chen William H.K. Lam Agachai SumaleeQingquan Li Zhi-Chun Li 《Transportation Research Part A: Policy and Practice》2012,46(3):501-516
To assess the vulnerability of congested road networks, the commonly used full network scan approach is to evaluate all possible scenarios of link closure using a form of traffic assignment. This approach can be computationally burdensome and may not be viable for identifying the most critical links in large-scale networks. In this study, an “impact area” vulnerability analysis approach is proposed to evaluate the consequences of a link closure within its impact area instead of the whole network. The proposed approach can significantly reduce the search space for determining the most critical links in large-scale networks. In addition, a new vulnerability index is introduced to examine properly the consequences of a link closure. The effects of demand uncertainty and heterogeneous travellers’ risk-taking behaviour are explicitly considered. Numerical results for two different road networks show that in practice the proposed approach is more efficient than traditional full scan approach for identifying the same set of critical links. Numerical results also demonstrate that both stochastic demand and travellers’ risk-taking behaviour have significant impacts on network vulnerability analysis, especially under high network congestion and large demand variations. Ignoring their impacts can underestimate the consequences of link closures and misidentify the most critical links. 相似文献
760.