基于BP人工神经网络的滑坡预测分析

文章以汶川地震引发的滑坡为研究对象,以震中距、地震烈度、坡度、前缘高程、坡高和岩性等影响坡体稳定性的因素为切入点,利用BP人工神经网络对实际坡体的稳定性进行了预测分析。结果表明,BP人工神经网络方法能有效预测坡体的稳定情况。     

Superpave-13沥青混合料高温稳定性分析

文章结合天水过境高速公路路面实体工程,对不同孔隙率条件下的Super-pave-13高性能沥青混合料进行了车辙试验及SPT试验分析。结果表明,要保证Superpave-13沥青混合料具有较好的高温稳定性,其压实孔隙率应控制在4%～6.5%范围内。     

U型桥台开裂原因分析及加固方案探讨

文章结合高速公路U型桥台开裂的典型工程实例,分析了U型桥台裂缝产生的原因,提出了相应的加固处治方案,并阐述了加固方案的实施要点与处治效果。     

基于Midas Civil的简易车桥耦合振动分析

文章以某40m预应力混凝土简支T梁为例,利用单轴车桥耦合振动数值模型及基于MidasCivil的简易车桥耦合振动模型对移动车辆荷载作用下的T梁结构动力响应情况进行计算分析。结果表明,基于MidasCivil的简易车桥耦合振动模型与数值模型的结构挠度峰值计算结果相差不大,可用于简单的车桥耦合振动分析。     

特大桥施工测量精度浅析

文章以兰渝铁路嘉陵江双线特大桥为工程背景,在介绍施工测量平面控制网的基础上,阐述了桥梁施工测量放样的精度要求及具体控制措施,分析了测量误差产生的原因,并提出了相应的测量精度评定方法。     

道路交通事故分析发展研究

近些年,我国交通事故量一直居高不下,而事故发生时车辆运行速度是分析事故原因、认定事故责任的重要内容,涉及保险理赔、法院审判等各个环节。目前分析事故原因,进行事故再现的主要途径是委托具有相关资质的事故鉴定机构进行速度重建,使用的方法主要有基于经验公式的事故重建、基于视频图像技术的事故重建、基于车载记录数据的事故重建和基于模拟软件的事故重建。文章主要介绍了交通事故分析的基本方法和发展方向。     

Identifying optimal data aggregation interval sizes for link and corridor travel time estimation and forecasting

With the recent increase in the deployment of ITS technologies in urban areas throughout the world, traffic management centers have the ability to obtain and archive large amounts of data on the traffic system. These data can be used to estimate current conditions and predict future conditions on the roadway network. A general solution methodology for identifying the optimal aggregation interval sizes for four scenarios is proposed in this article: (1) link travel time estimation, (2) corridor/route travel time estimation, (3) link travel time forecasting, and (4) corridor/route travel time forecasting. The methodology explicitly considers traffic dynamics and frequency of observations. A formulation based on mean square error (MSE) is developed for each of the scenarios and interpreted from a traffic flow perspective. The methodology for estimating the optimal aggregation size is based on (1) the tradeoff between the estimated mean square error of prediction and the variance of the predictor, (2) the differences between estimation and forecasting, and (3) the direct consideration of the correlation between link travel time for corridor/route estimation and forecasting. The proposed methods are demonstrated using travel time data from Houston, Texas, that were collected as part of the automatic vehicle identification (AVI) system of the Houston Transtar system. It was found that the optimal aggregation size is a function of the application and traffic condition.

A field evaluation case study of the environmental and energy impacts of traffic calming

This study quantifies the energy and environmental impact of a selection of traffic calming measures using a combination of second-by-second floating-car global positioning system data and microscopic energy and emission models. It finds that traffic calming may result in negative impacts on vehicle fuel consumption and emission rates if drivers exert aggressive acceleration levels to speed up to their journeys. Consequently by eliminating sharp acceleration maneuvers significant savings in vehicle fuel consumption and emission rates are achievable through driver education. The study also demonstrates that high emitting vehicles produce CO emissions that are up to 25 times higher than normal vehicle emission levels while low emitting vehicles produce emissions that are 15–35% of normal vehicles. The relative increases in vehicle fuel consumption and emission levels associated with the sample traffic calming measures are consistent and similar for normal, low, and high emitting vehicles.     

大型综合交通枢纽指路标志系统设置研究

城市大型综合交通枢纽由于其功能多样,辐射广泛,周边路网复杂,因此对其指路标志系统需要专门设计。文章以上海市虹桥综合交通枢纽指路标志系统为研究对象,从路网结构及交通流特性出发,将指路标志系统按出行者需求层次分为四级,并提出相应的指路标志设置原则及方法,供相关部门参考。     

隧道围岩体内位移监测分析

隧道围岩体内位移监测结论对于判断围岩稳定性和保证施工安全与工程质量起着重要的作用。文章以一高速公路隧道为依托,介绍了围岩体内位移测量设备和工作原理,并通过对其围岩体内位移检测数据的分析,提出了隧道围岩体内位移监测的注意事项。