注浆技术在桩底补强中的应用

针对桩底持力层缺陷、不同地层组成和件状,选用劈裂、高压旋喷等注浆技术进行补强,并介绍了注浆工艺、选用参数及注意事项,供参考应用。     

高铁湿陷性黄土隧道地基处理浅析

根据湿陷性黄土隧道工程特点,结合宝兰客专客运专线王家岔湿陷性黄土隧道地基加固处理的工程实例,阐述了洞口和洞内两种施工工艺不同的水泥土挤密桩施工方案,分析了隧道内水泥土挤密桩施工对其它工序的干扰和对工期的影响,以及施工振动对初支结构和围岩稳定的危害,提出了有效的控制措施.     

Enhancing stated preference surveys in transportation research: the contribution of geographic information systems

In this paper we argue that visualization, data management and computational capabilities of geographic information systems (GIS) can assist transportation stated preference research in capturing the contextual complexity of many transportation decision environments by providing respondents with maps and other spatial and non-spatial information in graphical form that enhance respondents' understanding of decision scenarios. We explore the multiple inherent contributions of GIS to transportation stated preference data collection and propose a framework for a GIS-based stated preference survey instrument. We also present the design concepts of two survey prototypes and their GIS implementation for a sample travel mode choice problem.     

兰州市五人制足球运动开展现状调查分析

本文运用文献资料法、专家访谈法、问卷调查法、数理统计法对兰州市五人制足球运动的开展规模、教练员情况、场地设施、社会参与人群状况等问题进行调查分析,提出了针对性建议,旨在为进一步推动兰州市五人制足球的健康快速发展,同时促进兰州市足球运动的普及与提高尽一份力。     

Evolution of the household vehicle fleet: Anticipating fleet composition, PHEV adoption and GHG emissions in Austin, Texas

In today’s world of volatile fuel prices and climate concerns, there is little study on the relationship between vehicle ownership patterns and attitudes toward vehicle cost (including fuel prices and feebates) and vehicle technologies. This work provides new data on ownership decisions and owner preferences under various scenarios, coupled with calibrated models to microsimulate Austin’s personal-fleet evolution.Opinion survey results suggest that most Austinites (63%, population-corrected share) support a feebate policy to favor more fuel efficient vehicles. Top purchase criteria are price, type/class, and fuel economy. Most (56%) respondents also indicated that they would consider purchasing a Plug-in Hybrid Electric Vehicle (PHEV) if it were to cost $6000 more than its conventional, gasoline-powered counterpart. And many respond strongly to signals on the external (health and climate) costs of a vehicle’s emissions, more strongly than they respond to information on fuel cost savings.Twenty five-year simulations of Austin’s household vehicle fleet suggest that, under all scenarios modeled, Austin’s vehicle usage levels (measured in total vehicle miles traveled or VMT) are predicted to increase overall, along with average vehicle ownership levels (both per household and per capita). Under a feebate, HEVs, PHEVs and Smart Cars are estimated to represent 25% of the fleet’s VMT by simulation year 25; this scenario is predicted to raise total regional VMT slightly (just 2.32%, by simulation year 25), relative to the trend scenario, while reducing CO₂ emissions only slightly (by 5.62%, relative to trend). Doubling the trend-case gas price to $5/gallon is simulated to reduce the year-25 vehicle use levels by 24% and CO₂ emissions by 30% (relative to trend).Two- and three-vehicle households are simulated to be the highest adopters of HEVs and PHEVs across all scenarios. The combined share of vans, pickup trucks, sport utility vehicles (SUVs), and cross-over utility vehicles (CUVs) is lowest under the feebate scenario, at 35% (versus 47% in Austin’s current household fleet). Feebate-policy receipts are forecasted to exceed rebates in each simulation year.In the longer term, gas price dynamics, tax incentives, feebates and purchase prices along with new technologies, government-industry partnerships, and more accurate information on range and recharging times (which increase customer confidence in EV technologies) should have added effects on energy dependence and greenhouse gas emissions.     

桥墩盖梁加固设计与施工探讨

以实际工程为背景，探讨了体外预应力加固桥墩盖梁的方法，经过优化设计采用钢锚梁进行预应力锚固。介绍了钢锚梁的具体构造，采用土木仿真有限元软件模拟分析，对盖梁混凝土承载能力、正常使用和持久状况应力、钢锚梁强度和稳定性进行研究，研究结果验证了加固措施的合理性，探讨了加固施工工艺。     

大吨位超长钢筋笼的制造与安装

简要介绍南京大胜关长江大桥主桥主墩深水基础钻孔桩超长钢筋笼的制造与安装。     

蕉门大桥增大截面法加固分析

以番禺蕉门大桥为例介绍了外包混凝土的加固理论及其优点。采用桥梁结构分析软件建立了结构分析模型,通过计算分析明确结构受力,提出了增大截面法加固桥梁的方案;通过复核计算证明了加固设计的可行性及合理性。其计算模型、简化方法及加固思路值得同类桥梁加固设计作为参考。     

浅谈箱形拱桥的维修与加固

文章针对目前钢筋混凝土悬链线箱形拱桥普遍存在的问题,介绍了采用粘贴钢板加固、改变结构受力体系、桥面补强层等3种方法,能有效地解决目前桥梁的维修和加固存在的问题。