膨胀土填方路基边坡滑坡成因分析及治理方案研究

文章依托南宁坛洛至百色高速公路K711+430～K711+480段膨胀土填方路基滑坡处治项目,开展膨胀土路基边坡滑坡的成因分析及治理方案研究。通过现场踏勘、理论分析、模拟计算,结合现场地质情况与交通安全因素,提出了抗滑桩治理方案,并进行施工关键技术总结。结果表明：干湿循环作用会造成膨胀土面开裂,水的浸入会造成深部膨胀土的膨胀,诱发滑坡;滑坡前缘抗滑桩对土体形成直接支挡,限制滑动体向前滑出,膨胀力向坡面释放;设计抗滑桩支挡方案后,正常工况与非正常工况下最不利滑动面稳定性系数均能满足要求。研究成果可为今后填方路堤病害处治工程提供参考。     

柔性支护技术在百色大道（一期）工程滑坡处治中的应用

文章以百色大道(一期)工程K18+720～K18+820段滑坡为工程背景,通过采用GeoStudio SEEP软件进行数值模拟分析,分析膨胀土在非正常工况下持续降雨入渗时边坡土体含水量变化和膨胀力的影响,提出了一种改进的滑坡处治柔性支护方案。结果表明,改进的柔性支护方案在膨胀土滑坡处治中效果良好,可供类似工程参考。     

基于湿度应力场理论的膨胀土边坡稳定分析

边坡土体中的膨胀力是导致膨胀土边坡失稳的主要原因之一。文章基于湿度应力场理论,采用ANSYS软件的热传导分析功能模拟分析边坡的降雨入渗以及膨胀变形,并采用有限元强度折减法对不同条件下边坡安全系数进行计算,分析了膨胀土边坡稳定规律,为膨胀土边坡处治提供理论依据。     

膨胀土路堑边坡病害处治技术

根据青临高速膨胀土路堑边坡的实际特点,分析了开挖边坡破坏的特点和原因,提出公路膨胀土路堑边坡设计支护方案和措施,有效地解决膨胀土路堑边坡病害问题。     

沿河膨胀填（弃）土滑坡群成因机制分析及处治研究

地形、物质组成、地质构造、水、外荷、地震等是填(弃)土滑坡破坏的主要因素,但其致灾机制仍未研究清楚。文章通过对膨胀土区沿河段填(弃)土滑坡案例进行分析,结合各种滑坡特征,研究了滑坡群成因机制,提出两大力学效应,并提出了滑坡治理措施,以期为类似滑坡处治提供工程参考。     

抗滑桩板式挡墙结合柔性支护在膨胀土中的应用与思考

文章以G80广昆高速公路南宁至百色路段膨胀土处治方案为例,在分析滑坡成因和计算滑坡土体物理力学参数的基础上,提出以抗滑桩板式挡墙结合柔性支护的边坡加固方案,并验算优化方案中钢板桩、抗滑桩、柔性支护的关键尺寸,同时对边坡加固施工的关键技术进行介绍,评价了加固效果。     

膨胀土路堑边坡防护技术探讨

文章基于膨胀土边坡稳定性影响因素及失稳机理,结合钦州至崇左高速公路膨胀土路段路堑边坡施工实例,提出了"两布一膜"与拱形骨架相结合的膨胀土路堑边坡防护技术方法,并阐述了该方法的基本原理与施做要点。     

南宁外环公路膨胀土堑坡土质特性及防护措施

文章以南宁外环高速公路的膨胀土(岩)路堑边坡为对象,基于边坡破坏的原因及特点,开展了膨胀土(岩)边坡的土性试验,并针对边坡的不同特点,提出了坡脚矮挡土墙+浆砌片石骨架+铺两布一膜、土工格栅柔性支护、土工格室柔性支护等多种不同土工材料的边坡支护处治方案。工程实施表明所采取的方案措施能经济有效地解决南宁外环高速公路的膨胀土路堑边坡问题。     

SNS柔性防护技术在膨胀土深挖路堑边坡中的应用

膨胀土边坡的防护与加固研究一直是岩土工程领域的一项重大课题,由于膨胀土的涨缩性,膨胀土边坡在防护过程中易发生脆性破坏,与刚性防护措施相比,柔性防护更能适应边坡的变形。本文针对膨胀土的特性,提出SNS柔性防护技术,对其防护机理进行了分析,阐述了SNS柔性防护技术在周南高速中的应用技术。     

柔性支护处治膨胀土路堑边坡施工工法

<正>完成单位:湖南顺天建设集团有限公司广西路建工程集团有限公司完成人员:杨和平、陆宏新、高雪山、唐双美、陈方红柔性支护处治膨胀土路堑边坡施工工法是在以往广西膨胀土地区筑路"逢堑必滑""屡治屡滑",造成严重地质灾害和生态环境破坏的技术背景下,西部交通建设重大科技项目"膨胀土地区公路修筑成套技术研究"课题组与施工单位项目部"提高膨胀土边坡施工质量"QC小组开展技术攻关,创立并实施柔性支护技术治理坍滑边坡而形成的。"柔性支护"这一技术创新和突破成为成套技术研究重     

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.     

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。     

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.     

盾构隧道管片接头抗剪力学性能研究

通过对南京长江盾构隧道环向管片接头进行的三组原型抗剪(无螺栓剪切、有螺栓逆剪和有螺栓顺剪)加载试验,分析研究了管片接头在剪力作用下的受力、变形和破坏特征,给出了管片接头混凝土接触面的静摩擦系数,得到了接头剪力主要由混凝土接触面承担、破坏形式为连接斜螺栓剪切延性破坏的结论。通过对管片结构的有限元数值模拟计算得出:接头处的剪力与轴力比小于接缝面的摩擦系数,管片不会发生相互错动,结构是稳定的。     

混合动力列车的应用前景展望

本文阐述了混合动力列车的技术特点及其相应优势与劣势,同时介绍了其在国内外的研究动向,并对其应用前景进行了展望。尽管该类新型铁道车辆的续航能力、电池寿命以及成本等相关问题目前仍有待改善,但以其对城市环境的美化作用与优越的舒适驾乘性能,以及高效节能、绿色环保的显著优势,依然不失为一类充满前景的新型轨道交通运输方式。     

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。     

Evaluation of pedestrian crosswalk level of service (LOS) in perspective of type of land-use

In India pedestrians usually cross the road at mid-block crosswalks due to ease of access to their destination or the development of adjacent land use types such as shopping, business areas, school and residential areas. The behaviour of pedestrian will change with respect to different land use type and this change in behaviour of pedestrian further reflects change in perceived level of service (LOS). So, it is important to evaluate the quality of service of such crossing facilities with respect to different land-use type under mixed traffic conditions. In this framework, pedestrian perceived LOS were collected with respect to different land-use type such as shopping, residential and business areas. The ordered probit (OP) model was developed by using NLOGIT software package, with number of vehicles encountered, road crossing difficulty as well as safety considered as primary factors along with pedestrian individual factors (gender and age), land-use type and roadway geometry. From the model results, it has been concluded that perceived safety, crossing difficulty, land-use condition, number of vehicles encountered, median width and number of lanes have significant effect on pedestrian perceived LOS at unprotected (un-signalized) mid-block crosswalks in mixed traffic scenario. The inferences of these results highlights the importance of land use planning in designing a new set of pedestrian access facilities for unprotected mid-block crosswalks under mixed traffic conditions. Also the study results would be useful for evaluating pedestrian accessibility taking into account different land-use type and planning required degree of segregation with vehicular movement at unprotected mid-block crosswalk locations.     

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。     

围岩空间变异性对隧道结构可靠度的影响分析

采用随机场模型能够有效地模拟围岩参数的空间变异性。文章将局部平均随机场理论、有限差分法和Monte-Carlo模拟结合在一起,得到了Monte-Carlo随机有限差分法,基于该方法编制了可考虑围岩空间变异性的隧道结构可靠度计算程序;并将围岩密度、弹性模量和内摩擦角等参数视为三维正态随机场,研究了围岩的竖向与水平向相关距离的变化对隧道结构可靠度的影响。计算结果表明,围岩空间变异性会显著影响隧道结构的可靠度,为了获得更为经济合理的支护方案,在支护设计时考虑围岩参数的空间变异性很有必要;围岩竖向或水平向相关距离的增大均会引起隧道结构失效概率的增加,但影响程度不同;隧道结构失效概率对围岩竖向空间变异性更加敏感,故在工程勘察费用较少时,可考虑将勘察费用更多地投入到竖向相关距离的勘测,水平向相关距离可参考已有经验数据取值。