公路隧道施工要点的掌握与控制

公路隧道施工准备阶段的原材料及配比、测量控制、人员设备、施工方案的审查和确认,施工过程中洞口开挖、洞身钻爆、初期支护、二次衬砌等技术要点以及在此过程中遇到的地质断层、软弱围岩、小塌方、涌淋水等问题处理。     

配比建筑垃圾再生材料大型固结试验分析

本文利用室内大型固结试验,分析了建筑垃圾再生材料三种配比、四种压实度在不同荷载条件下的压缩性质,通过研究不同配比材料的应变与荷载的关系、孔隙比与配比的关系、压缩系数与配比的关系、应变与配比的关系及应变与压实度的关系,得出:建筑垃圾再生材料的变形随着荷载的增大而增大,不同的压实度会使各配比的孔隙比的峰值有所不同,砖渣的含量对建筑垃圾再生材料压缩性能有较大影响,在进行现场施工时,应注意控制砖渣含量。     

二灰土配合比设计与施工质量控制

在济南绕城高速公路东线工程建设中,结合当地实际料源、对比现场实际养生方法,介绍了二灰土配合比室内设计程序,论证了配合比由室内设计向施工阶段的转化,以及配比设计中采取措施的合理性.     

基于模拟试验的固化风积沙路用性能研究

为系统、全面地研究固化风积沙混合料的路用性能和耐久性,文章以毛乌素沙地的风积沙为主要筑路材料,采用水泥、石灰、石膏和KL-ST76固化剂稳定风积沙,确定了四种混合料最佳配比,并对四种配比混合料的力学性能(抗压强度、劈裂强度和抗压回弹模量)、抗冻性能、抗干缩性能以及抗温缩性能进行了试验研究。结果表明:KL-ST76固化剂稳定风积沙混合料的无侧限抗压强度、劈裂强度、抗压回弹模量及抗干缩性能、抗温缩性能明显高于其他三种配比混合料;四种配比混合料的抗冻性能相近。     

响应面分析法在隧道相似材料试验中的应用

基于数理统计响应面分析法中的二次回归通用旋转法,将粘聚力与内摩擦角作为铁路隧道软弱围岩的研究指标:以重晶石、石英砂和凡士林等混合物作为铁路隧道软弱围岩的相似材料,通过应力控制式三轴试验仪进行常规三轴试验;利用非线性同归分析的方法对实验结果进行分析,分别得出相似材料配比与围岩粘聚力及内摩擦角的变化规律.综合考虑粘聚力与内摩擦角两个指标之后,最终得出与模型试验所需围岩条件相匹配的相似材料的重晶石、石英砂与凡士林的最佳配比为9.25:4.56:0.67.     

环氧砂浆封锚技术

环氧砂浆封锚是以一定配比的灰料和乳液现场拌和泵送至模板的预应力封锚工艺,具有配比易控,施工简单,耐严寒、耐开裂等特点。文章以乌兰木伦河3号桥环氧砂浆封锚施工为例,介绍了环氧砂浆材料耐寒抗裂特点及施工工艺。     

生石灰改良高液限黏土的无侧限抗压强度试验研究

为研究高液限土的化学改良效果,文章以广西宁明高液限黏土为对象,在分析基本工程特性的基础上,采用生石灰、二灰(生石灰+水泥)为添加剂,进行不同配比处治土的液塑限试验、击实试验及无侧限抗压强度试验,研究石灰的改性方法及经处治后的特殊土的物理力学特性。研究表明:掺石灰对高液限土强度的增长效果显著,当掺量为5%、7%时均能满足CBR值3%且胀缩总率0.7%的规范要求。     

富水软弱地层盾尾单双液多序注浆及效果研究

在富水易坍塌的软弱地层中,盾尾注浆施工存在一定的技术难度。文章针对该技术难题,从浆液配比及施工工艺改进两个方面进行了深入研究,分析了水泥、膨润土、粉煤灰及水玻璃4种常用注浆材料的7种浆液配比性能和适用性,提出了富水软弱砂层中的单双液壁后多序注浆工艺。该注浆工艺既控制了双液的快速凝结又保证了有效充填,是一套适用于富水易坍塌地层、有利于地面沉降控制的盾尾注浆技术。     

机制砂在C50混凝土预制梁中的应用分析

文章分析了机制砂的配比、石粉含量限值和细度模数的差异,通过配比试验检验了C50混凝土预制梁中运用机制砂的效果,并提出了相关质量控制措施。     

沥青罩面改造旧水泥混凝土路面施工技术

结合湖南浏阳市浏阳河路沥青罩面改造旧水泥混凝土路面工程实际,从病害处理、材料及配比选用、施工工艺等几方面,对利用沥青罩面改造旧水泥混凝土路面的施工技术进行探讨.     

Analysis of factors affecting the choice of route of pedestrians

Pedestrians as compared to vehicular traffic enjoy a high degree freedom of movement even in heavily congested areas. Consequently, there are more alternative links available to pedestrians between a given origin‐destination (O‐D) pair. This paper describes a study done by the University of Calgary to evaluate the factors affecting the choice of route on intra‐CBD trips or trips within the Central Business District (CBD).

An origin destination survey conducted in downtown Calgary, Alberta enabled the identification of the most significant factors influencing the choice. These factors were analyzed in relation to the physical characteristics of the location, personal characteristics of the trip maker and the type of the trip.

It appears that most people chose the shortest link and factors such as the level of congestion, safety or visual attractions were only secondary. This suggests that the length should be made a major consideration when planning and designing pedestrian links.     

实现多组态计量软件集中监控的可行性分析

天然气自动计量系统有多种组态软件,由于软件的不相通性,造成了计量系统数据采集的通用性差、数据传输与入库的时效性差、数据利用的可靠性低.结合各组态软件的实际情况,从设计上充分利用Oracle大数据处理能力以及Partition(分区表)的特性,实现历史数据的存储,应用WebService与COM+数据访问组件提供多层数据访问架构,采用OPC与DDE工业数据交换协议,实现了各站场计量数据的实时上传,为连续数据采集和实时监控提供了可能,节约了改造成本.     

注汽管道承压能力评估和实物试验验证

基于失效评估图技术对某注汽管道进行了承压能力评价,给出了管线在不同腐蚀壁厚情况下的极限承压能力和极限裂纹尺寸。并利用实物爆破试验验证了评价方法的安全性和有效性,通过对爆破断口进行宏观和微观分析,发现管段的开裂属于脆性开裂。     

Non-parametric analyses of efficiency of airports

This paper estimates the efficiencies and productivity changes of 12 international airports in the Asia-Pacific region based on data from 1998 to 2006. We apply stochastic frontier analysis (SFA) to compute efficiency estimates and use the Malmquist productivity index (MPI) to analyze productivity changes. We use the SFA model with a translog-type production function after testing the statistical hypotheses. According to the results of the SFA hypothesis tests, airports have experienced a technological regression; the deviations from the efficiency frontier are caused more by technical inefficiency than random noise. However, the inefficiency was found to decrease. The MPI reveals a declining trend resulting more from technological change than from efficiency change, with a decrease in inefficiency. Taken together, both the hypothesis tests and the MPI not only provide consistent conclusions, but also suggest that airports should concentrate on technological progress.     

波纹管应力分析研究进展

评述了波纹管应力理论研究方法的进展情况，围绕解析法、工程近似法和数值法，对波纹管理论研究中的一些主要成果作了较详细的回顾和总结，对各种研究方法作出了评价，展望了亟待解决的一些问题。     

输油管道中原油乳状液的流变性研究

原油乳状液的流变性是原油开采后在管道中输送的重要研究方面,为了更好地研究这一性质,采用电动搅拌机、偏光显微镜以及流变仪等仪器来测定不同含水率的原油乳状液在不同条件下的黏度,观测不同含水率的原油乳状液在偏光显微镜下的形态。并且分别对原油乳状液的黏度与含水率之间的关系以及与剪切速率之间的关系进行研究,初步确定了所测区块原油乳状液的转相点以及该区块原油乳状液的流变特性,为生产中的油气集输提供了理论依据。     

城市轨道交通杂散电流监测系统概述

介绍了城市轨道交通工程中杂散电流不同的监测系统的构成,分析了集中式、分散式和智能型等监测系统的配置和功能,以及智能型实时在线监测系统的重要意义,为轨道交通工程杂散电流监测系统的选择与应用提供参考。     

埋地管道防腐保温层失效评价

明确埋地管道防腐保温层的技术评价标准,对埋地钢质管道的安全运行,延长管道使用寿命具有重要意义。为了对埋地管道防腐保温层做出有效评价,从间接检测与开挖检测2个方面,结合现场检测数据,提出了基于防腐保温层的电流衰减率、绝缘电阻率、质量状况与厚度的分级评价标准及基于4种评价指标的综合评判方法。工程实践表明,该评价标准对防腐保温层是否存在失效能做出有效判断。     

Preliminary results of an analysis of areas of influence in Shanghai

The main deficiency of most current modeling approaches to transportation can be identified as neglect of the integration of existing geographical knowledge in regard to the ex ante transport/land use modeling approaches, with its focus on territorial dynamics and theory development. This paper addresses this aspect of the problem by introducing a theoretical and methodological framework for the analysis of the interrelationship between land uses. The analysis attempts to determine to what extent the functional land use in a city can be considered an ordered pattern. The order sought does not rely on purely spatial configurations, but on the correlation of transportation and land use. The first section of this paper focuses on theoretical considerations. It stresses the fact that conventional approaches do not apply in the present context. It then suggests an alternative based on areas of influence and measured in terms of level of attractance of land uses. The second describes a procedure based on this alternative following the remarkable contribution of Hanjoul, Beguin and Thill. An application of this procedure to the analysis of Shanghai is then examined. Finally, an evaluation of the strategies for optimizing the interrelationship between land uses is presented. The paper concludes with a possible research agenda.     

Direct analysis of the perceived importance of attributes of reliability of travel modes in urban travel

Reliability of travel modes was found to be the most important characteristic of transportation systems in several attitudinal investigations of individual travel behavior. This paper represents the first part of a research effort aimed at gaining a better understanding of the characteristics of reliability of transportation modes in urban travel. In this research, reliability characteristics are identified; their importance relative to each other is assessed, and an insight into possible structure of an objective reliability index is discussed. The research is based on perceived values of reliability, which were identified through a large attitudinal survey conducted in the Chicago metropolitan area.