路基冲击压实效果分析

冲击压实的被冲压体响应是目前尚未解决的理论问题。基于应变能与冲击能分布密度相等的基本原理,假定:冲压n遍后的被冲压体为一维问题,冲压影响深度h0处应变为零,应变与弹性模量线性变化,建立了单次冲击能量、遍数等与土体压实度的关系,在施工参数与效果间建立了关联。结果表明,以相同的设备参数进行施工时,冲压影响深度随冲压遍数的增加而减小;前几遍冲压能影响较大深度,而后续冲击的影响逐步局限于上部土体。通过某砂性土工程实例,分析预测得知,单层80 cm冲压35遍仍达不到规定的压实度要求,因此,实体工程中需采用分层压实的措施。所以,本研究可用于对冲压效果的预测,也可在冲压目标明确的情况下预估需要进行冲压的遍数。     

冲压技术在阿尔及利亚东西高速公路中的应用

为确保阿尔及利亚东西高速公路高填路基的填筑质量,针对C1B5S填料建立一段试验路基,在填料压实度和变形模量双控标准的基础上,采用冲击压路机进行补压增强,研究其碾压遍数与压实度、沉降量的关系,以确定最佳施工工艺;同时对代表性工点进行工后沉降观测分析,结果表明冲压补强的高填路基工后沉降量是路基本体高度的0.08%～0.10%,路拱横坡改变小,对控制高填路基的差异沉降和工后沉降效果良好。     

旧式组合式桥梁护栏提升改造及应用

早期的一种组合式桥梁护栏已不满足现阶段安全防护需求。经过充分的调查研究,并在再利用原护栏混凝土基座的基础上,提出一种植筋加高改造结构。按照《公路护栏安全性能评价标准》的规定组织实车足尺碰撞试验,试验结果表明,护栏改造结构防护等级达到六(SS)级,安全性能可靠。该结构已在实际工程中应用,不仅提高了桥梁护栏的安全防护能力,而且缩短了施工周期、降低了工程造价,取得了良好的应用效果。     

The environmental impact of distribution to retail channels: A case study on packaged beverages

This study aims to quantify the environmental impact of two retail distribution networks and offer consumers a channel that is more beneficial to the environment. The environmental impact of replenishing the packaged beverages sold in convenience stores (CVSs) and hypermarkets is assessed using the streamlined life-cycle assessment (LCA) approach. In this study, the life-cycle impact assessment (LCIA) for packaged beverages up to the point of sale illustrates the distribution-level environmental impacts of truck transportation. The matched-pair t-test shows that the environmental impacts of transporting 1800 cartons of 24-pack/10 oz. beverages to be sold in Carrefour and 7-11 stores is different at a significance level of 0.1. The transport-focused LCA is used to improve the understanding and compare the environmental characteristics of the two distribution and retail systems. This study constitutes a vehicle for communicating to both internal and external stakeholders the environmental profiles of distributing the same product sold through two retail channels.     

Is rail cleaner and greener than bus?

The popular consensus is that urban passenger rail is more environmentally friendly than urban passenger bus. This position is largely associated with the key energy source for each mode, respectively electricity and diesel, where electric vehicle use will typically result in local air quality improvements away from the electricity generation source. Surveys of community perceptions reflect this sentiment; however the relationship between the source of energy and its resultant emissions is not something that citizens fully understand. There is a general lack of awareness of the resource base of much of electricity generation in some countries. Where generation sources are suitably renewable or low-carbon, electricity use will offer greenhouse gas abatement potential. However, in countries which still rely heavily on coal-fired power stations, such as Australia, abatement is not as assured and estimating emission outcomes can require careful assessment. Supporters of alternatives to diesel use can focus on the future supply of fossil-fuels, an argument which has merit; however such arguments are often confounded with environmental qualities related to local air pollution and enhanced greenhouse gas emissions. This paper takes a close look at the greenhouse emissions that are associated with urban rail and bus in Australia. Estimated intensities, when presented in the context of effective service delivery (primarily in terms of emissions per passenger kilometre), raise questions about the distortions that are present in the widespread promotion in Australia (at least) of rail as a more environmentally friendly and hence a sustainable mode of urban passenger transport than bus.     

How to best address aviation’s full climate impact from an economic policy point of view? – Main results from AviClim research project

The interdisciplinary research project AviClim (Including Aviation in International Protocols for Climate Protection) has explored the feasibility for including aviation’s full climate impact, i.e., both long-lived CO₂ and short-lived non-CO₂ effects, in international protocols for climate protection and has investigated the economic impacts. Short-lived non-CO₂ effects of aviation are NO_x emissions, H₂O emissions or contrail cirrus, for instance.Four geopolitical scenarios have been designed which differ concerning the level of international support for climate protecting measures. These scenarios have been combined alternatively with an emissions trading scheme on CO₂ and non-CO₂ species, a climate tax and a NO_x emission charge combined with CO₂ trading and operational measures (such as lower flight altitudes). Modelling results indicate that a global emissions trading scheme for both CO₂ and non-CO₂ emissions would be the best solution from an economic and environmental point of view. Costs and impacts on competition could be kept at a relatively moderate level and effects on employment are moderate, too. At the same time, environmental benefits are noticeable.     

The impact of high-speed rail investment on economic and environmental change in China: A dynamic CGE analysis

This study investigates the impact of high-speed rail investment on the economy and environment in China using a computable general equilibrium (CGE) model. The analysis is implemented in a dynamic recursive framework capturing long-run capital accumulation and labor market equilibrium. A national level impact was simulated through direct impact drivers including land use conversion, output expansion, cost reduction, productivity increase, transport demand substitution and induced demand. The results suggest that rail investment in China over the past decade has been a positive stimulus to the economy, while the effect on CO₂ emissions generation has been large. Overall, the economic impacts of rail investment are achieved primarily through induced demand and output expansion, whereas the contribution from a reduction of rail transportation costs and rail productivity increases were modest. In addition, negligible negative impacts were found from land use for rail development and the substitution effect among other modes. Emissions reduction from substitution of rail for other modes was small and offset by output expansion due to lowered rail transport costs and induced demand.     

加入WTO对我国建材工业的影响

介绍了我国加入WTO后的权利和义务,从正负两个方面分析了“入世“后对我国建材工业的影响,并根据我国实际情况,提出了相应对策.     

不同冲击角度对两轮车骑行者保护试验区域伤害的研究

对交通事故数据的研究表明,两轮车骑行人也面临很高的受伤风险,各新车评价规程也开始对骑行人保护做出要求。根据中国保险汽车安全指数2023版规程的变化,通过选取符合要求的部分车型开展对比试验,分析在不同撞击角度下的头型伤害差异。试验结果表明,在撞击角度为45°时的伤害值大于撞击角度65°时的伤害值。     

Office location — city or suburbs?

Suburban offices constitute a growing proportion of the metropolitan office stock in Melbourne. The relocation of around 1700 Coles Myer employees from the Central Business District to Tooronga, 8.5 km south east from the GPO, is an example of office decentralisation. A study of the resultant impacts arising from the relocation has been conducted utilising a before-the-move and after-the-move survey of Coles Myer employees. Both surveys generated response rates in excess of 60%. Office relocation can have various short and long term impacts on employees and will influence decisions relating to residential location, car ownership and the resultant travel and activity patterns. It is not until these impacts are quantified that planners can gain acceptance for strategies designed to minimise the negative impacts associated with dispersed employment opportunities.This paper discuses the suburbanisation of office employment in Melbourne and studies the travel related effect on the employees, whose headoffice is relocated from the CAD to a suburban location. One of the great challenges for transport in the 90's will be the successful management of office location and the resultant impacts on travel.Abbreviations CAD Central Activities District; the CAD is defined as a slightly larger area than that previously referred to as the Central Business District (CBD)