胶膜对软粘土侧压力系数K0测试结果的影响

软粘土的侧压力系数K0值是上海地区地下工程设计时不可缺少的参数之一,应用专门的K0试验仪进行试验,对比试验表明K0仪的胶膜材质和厚度对软粘土的测试结果有明显影响。     

测定土体回弹模量的两种室内试验方法探讨

本文根据大量的土工室内试验数据,对土体回弹模量两种试验方法获得的数据进行了综合比较分析,并结合相关工程基坑坑底隆起量的估算与实测数据的对比,提出了室内土体回弹模量试验方法的建议。     

曲线梁桥设计时冲击系数的确定

由于曲线梁桥有别于直线梁桥的特殊结构,冲击系数确定与直梁桥区别较大.对曲线梁桥在车辆荷载作用下的冲击系数确定做简要的分析,并进行了实例计算论证.     

压力管道膨胀节稳定性试验的不确定度评定

文中主要按照GB/T 12777—2019,使用膨胀节综合性能试验装置对压力管道膨胀节进行了稳定性试验。通过对施加试验压力前后的波距测试结果的不确定度评定,进一步计算出稳定性试验测试结果的不确定度,计算得到稳定性测试结果的相对扩展不确定度为1.21%。     

拉力型锚索锚固段长度的一种确定方法

文章分析了锚杆拉拔试验的结果,提出了非全长粘结型锚索锚固段剪应力沿长度分布的二次抛物线模式,以及确定锚固段长度的合理方法,并以工程实例说明了文中提出的锚索锚固段长度计算方法的合理性.     

某2037型轻型汽车排放Ⅰ型试验不确定度评估

对某2037型压燃式发动机轻型汽车进行5次排放Ⅰ型试验,根据中国合格评定国家认可委员会和中国国家计量技术规范对不确定度的定义及其评定方法和表述方式,灵敏系数的定义及计算方法,对该组试验结果中除气态污染物外的颗粒物质量及粒子数量测量结果进行不确定度分析及评定,尝试各影响因素的灵敏系数并将该系数应用于不确定度评定计算过程中,从而得到更加客观全面的不确定度评定结果。     

载荷试验确定粉喷桩复合地基承载力的探讨

静载试验是目前确定复合地基承载力较为可靠的原位测试技术之一。文章结合某路基软土处理工程实例,分析了由载荷试验确定复合地基承载力的几种常用方法,提出采用相对沉降法来确定粉喷桩复合地基承载力,同时采用双曲线拟合法或回弹法来检验其方法的可靠性,以保证水泥粉喷桩处理软土地基的加固效果。     

基于运能匹配的公铁联运物流中心建设规模确定方法

为解决公铁联运物流中心建设规模确定方法普遍缺少考虑各功能区协调匹配性的问题,对公铁联运物流中心建设规模确定的主要影响因素及工作特征进行了分析,运用时空消耗理论建立了公铁联运物流中心运能匹配模型,并提出了基于运能匹配的铁路、公路、仓储及总用地规模计算方法。该方法将物流中心内货物的流转过程抽象为时空消耗过程,将复杂问题简单化,并能充分体现公路、铁路、仓储设施之间的协调匹配关系。应用该方法对某公铁联运物流中心建设规模进行了测算,得到铁路、公路、仓储和总用地规模与实际值的偏差分别为6.9%、3.7%、4.2%、5.2%,均在7.0%以内,表明该方法是合理有效的。     

桥梁工程中试验检测的作用和方法

结合新疆地区的地形来分析桥梁工程试验检测容易出现的问题,提出解决的方法。     

GB/T 4334—2020晶间腐蚀试验方法的解析

文中主要对GB/T 4334—2020标准中主要修订的内容进行介绍和分析:对标准名称和方法E的名称进行了修订;废除了方法D,增加了方法F和方法G,增加了对各种方法及其特点的说明,明确了方法E、方法F、方法G的适用范围;对取样方法和尺寸进行了调整,对敏化处理制度进行了调整,对方法E的弯曲参数进行了变更.修订后的标准更加完...     

软土路基全过程沉降量预测方法研究

全过程沉降量是软土路基上路堤工程设计的关键要素之一。文章系统介绍了几种常用的全过程沉降预测方法,评价了其各自特点,并提出了相应的改进措施,最后通过典型事例验证了改进方法的有效性和实用性。     

强夯法在高速公路深层软弱土层处治中的应用

文章通过介绍广西岑梧高速公路穿越K46 315~K46 570段人工填土区的处治,详细地介绍了在该特定地质环境条件下对公路路基深层软弱层的处治设计思路,对类似工程的设计以及丰富公路工程的软土处理方法有一定的借鉴价值。     

Spatial variation of roadside C2–C6 hydrocarbon concentrations during low wind speeds: A note

This Note describes an investigation of spatial variations in the ambient concentrations of hydrocarbons in the vicinity of a suburban motorway during five consecutive weekday morning peak periods of unusually warm and calm conditions. Background-corrected downwind concentrations representing the influence of the motorway source were found to be strongly dependant on wind speed and direction. The ambient ethene-to-acetylene concentration ratio was greatest close to the roadside and the effect of wind speed on the ratio had different average profiles for main wind directions due to different rates of dispersal. Higher values were obtained using background-corrected concentrations.     

Spatial variation of roadside C2–C6 hydrocarbon concentrations during low wind speeds: Validation of CALINE4 and COPERT III modelling

The CALINE4 model is widely used to predict the effect of vehicle emissions on ambient concentrations close to roadways. It requires an evaluation of the rate at which different air pollutants are emitted by vehicles, taking into account things such as vehicle flow, velocity, type and age. For Europe the databases of the COmputer Program to calculate Emissions from Road Transport (COPERT) are combined with local vehicle details to obtain site-specific emission factors for dispersion modelling. The ability of CALINE4 to predict the spatial variation of hydrocarbon concentrations downwind of a motorway is assessed, as is the accuracy of COPERT III composite emission factors for several hydrocarbon compounds. The concentrations of seven traffic-associated compounds is found at three locations downwind and upwind of a motorway. Modelled and measured background-corrected downwind concentrations are compared on three bases: daily peak hour concentrations, mean concentrations, and a set of model evaluation parameters.     

A system dynamics model of CO2 mitigation in China’s inter-city passenger transport

Mitigation of greenhouse gas emissions from transportation has become increasingly important and challenging especially for developing countries. This paper takes the inter-city passenger transport in China as a case, and develops a system dynamics model for policy assessment and CO₂ mitigation potential analysis. It is found that the future demand for China’s inter-city passenger transport is expected to be large, with the turnover volume growing at a rate of 9% per annum and amounting to 6600 billion p-km in 2020. Major emissions reduction potential exists in inter-city passenger transport. In 2020, comparing to the case without any specific policies stressing mitigation, the reduction of CO₂ emissions ranges from 26% to 32% under those scenarios with policy controls. Sensitivity analysis reveals that the CO₂ mitigation will be best achieved by accelerating the development of railway network, together with slowing down the extension of highway network and imposing fuel taxes.     

The costs and benefits of reducing SO2 emissions from ships in the US West Coastal waters

Potential costs and benefits of policy options for reducing offshore ship pollution are examined using a meta-analysis of studies synthesized regionally for the US West Coast. Net benefits of reducing SO₂ emissions from cargo ships in the US West Coast waters are found to range between $98 million and $284 million, annually; the benefit–cost ratio varies between 1.8 and 3.36, depending on the size of the control area and the sulfur content limit. The results show that about 21,000 tons of on-land equivalent SO₂ emissions or about 33% of SO₂ emissions from all mobile sources in California in 2005 can be reduced annually if the US West Coast exclusive economic zone is designated as an International Maritime Organization-compliant SO_x emission control area (SECA) with fuel-sulfur content not exceeding 1.5%. The analysis demonstrates that designating this area reduces more emissions than establishing a smaller zone at a lower but favorable benefit-cost ratio. Control measures that require 0.5% low-sulfur fuels reduce more SO₂ emissions, and also may have higher net benefits. Technological alternatives may achieve benefits of emissions reductions on the US West Coast across higher ranges of potential fuel prices. Combinations of fuel switching and control technology strategies provide the most cost-effective benefits from SECAs on the US West Coast and other world regions.     

PM10 concentrations and the size distribution of Cu and Fe-containing particles in Istanbul’s subway system

In this study, PM₁₀ concentrations, as well as the size distributions of Fe-containing and Cu-containing particles are measured in six subway stations in Istanbul. The average daily PM₁₀ concentrations are found to vary considerably. They were also found to be significantly higher than the levels found at urban air quality stations. Further, the relative abundance of Fe-containing particles among the particles of size >2.1 μm collected in the metro stations is 3.5-8 times higher than in the in the Istanbul atmosphere.     

The effectiveness of a European speed limit versus an international bunker-levy to reduce CO2 emissions from container shipping

In the fight to reduce CO₂ emissions from international shipping, a bunker-levy is currently under consideration at the International Maritime Organization (IMO). Faced with the inability of the IMO to reach an agreement in the short term, the European Commission is now contemplating a unilateral measure of a speed limit for all ships entering European Union (EU) ports. This paper argues that this measure is counterproductive for two reasons. Firstly, because it may ultimately generate more emissions and incur a cost per ton of CO₂ which is more than society is willing to pay. Secondly, because it is sub-optimal compared to results obtained if an international bunker-levy was to be implemented. These elements are illustrated using two direct transatlantic services operated in 2010.