装备项目风险管理体系的研究

首先对装备项目全寿命周期内各阶段风险管理的工作内容、相互关系进行了分析,参考系统工程三维结构概念和国内学者提出的风险管理体系的论述,提出了新的三维风险管理体系概念模型,对结构、要素进行了定义和阐述,对其理论指导作用和实际使用意义做了初步探讨,提出了进一步研究的方向,以期对装备项目的风险管理工作和理论研究起到参考和促进作用.     

钢筋混凝土桥柱新配筋方式研究

该文结合轴心抗压试验,介绍了钢筋混凝土桥柱的配筋方式,可供类似结构设计借鉴参考。     

Simulation of city bus performance based on actual urban driving cycle in China

This paper establishes the simulation model of a city bus on the basis of the EQ6110 bus prototype and its experimental data. According to the actual urban driving cycle, the fuel economy and the traction performance of the EQ6110 city bus have been simulated, and factors such as the driving cycle, the loss of power to engine accessories, the gear-shifting strategy, the fuel shut-off strategy of the engine, etc., which influence on the bus’s fuel economy, are also quantitatively analyzed. Some conclusions are drawn as follows: (1) driving cycles have a great influence on the fuel economy of a city bus; (2) under the typical urban driving cycle of the public bus in China, the engine fuel shut-off strategy can save about 1 to 1.5 percent of the fuel consumption; and (3) the optimized gear-shifting rules can save 6.7 percent of the fuel consumption. Experimental results verify that the fuel economy for the EQ6110 public bus is improved by 7.2 pecent over the actual Wuhan urban driving cycle of the current public bus in China.     

碎石桩处理高液限土地基的离心试验研究

高液限土是一种对工程有害的特殊土。为了处治高液限土地基,对室内土工离心模型试验进行分析,利用离心机产生离心力场,提高模型土体的体积力,形成人工重力。模拟高液限土地基在碎石桩处理后的固结性状,观测地基模型的变形和沉降。试验结果表明,碎石桩复合地基措施确实能改善地基的受力和变形性状,极大增强地基的稳定性。     

Development of analytical procedure for selection of control measures to reduce congestions at various freeway bottlenecks

Variable speed limit (VSL) and ramp metering (RM) affect freeway traffic operations in different ways and, accordingly, result in different effects on system travel time. The primary objective of this study is to propose an analytical procedure to help determine which control measure should be selected given different freeway bottlenecks and traffic conditions. The bottlenecks considered included an isolated merge bottleneck, a merge bottleneck with a closely spaced upstream off-ramp, and a diverge bottleneck with a closely spaced upstream on-ramp. Two RM and a VSL control strategies were considered, including the ALINEA, ALINEA/Q and feedback based VSL. The maximum achievable improvements in system efficiency by various control measures were calculated and the results were tested using modified cell transmission models. A coordinated control strategy that combined ALINEA/Q and VSL control was also proposed. The effects of VSL and RM control on system travel time at different freeway bottleneck areas were compared to identify the applicable conditions of different control measures. The analytical procedure was proposed for the selection of control measures at different bottlenecks and the ex-ante estimation of control effects were also discussed.     

Implementing a GPU-based numerical algorithm for modelling dynamics of a high-speed train

This paper discusses the initiative of implementing a GPU-based numerical algorithm for studying various phenomena associated with dynamics of a high-speed railway transport. The proposed numerical algorithm for calculating a critical speed of the bogie is based on the first Lyapunov number. Numerical algorithm is validated by analytical results, derived for a simple model. A dynamic model of a carriage connected to a new dual-wheelset flexible bogie is studied for linear and dry friction damping. Numerical results obtained by CPU, MPU and GPU approaches are compared and appropriateness of these methods is discussed.     

地铁线路纵断面调坡上下限线法及其应用

为提高地铁线路纵断面精调效率,避免调坡后出现相邻区段坡段超限,利用上下限线法,建立轨面线允许上下浮动的上下限线范围进行辅助调坡,协同调整变坡点和竖曲线半径与上下限线关系进行纵断面优化,并应用于福州市轨道交通2号线隧道纵断面掘进偏移事故中。结果表明： 1）采用上下限线法可以快速判断盾构掘进是否竖向超限,并方便快速确定调坡方案,避免多次调坡反复验算问题; 2）采用上下限线法可以避免对已实施段盾构隧道的调坡超限; 3）上下限线法成功应用在福州市轨道交通2号线隧道偏移事故中,采用该方法能在短时间内找出指导后续推进的调整方案,避免盾构停机造成的工程风险。     

某软土地铁车站基坑纵向滑坡事故分析

狭长形地铁车站基坑在分层开挖过程中会形成临时纵向多级边坡。当挖方边坡位于软弱地层时,如果设计或施工不当将会面临基坑纵向失稳风险。针对某软土地铁深基坑纵向滑坡事故案例,在考虑参数变异性的基础上利用极限平衡法对坑内临时边坡展开调查分析,并从工程角度对土坡发生深层滑移破坏的原因进行探讨。调查结果表明： 第1级边坡的坡度是影响整体稳定性的关键因素,1∶1.75（V∶H）的施工坡度不能满足下卧软弱淤泥质土条件下该局部边坡的稳定性（失稳概率高达88.92%）,只有当坡度缓于1∶3时才能保证安全。为防止此类临时挖方边坡失稳,最后给出考虑土体强度参数变异性的最优边坡坡度。     

基于山区复杂路段下的车辆主动限速控制系统研究

山区复杂路段交通事故频发,行车安全问题亟待解决,因此研究该路段下的主动限速控制技术具有重要意义。本文阐述了主动限速控制系统的原理与构成,并且对车辆的运行安全车速进行了分析与建模,提出了主动限速的控制策略。最后通过对该系统软硬件进行了调试,初步验证了其可行性比较合理,能够指导驾驶人的行车安全。     

杭州地下空间发展展望与研究

地下空间作为城市有机体的一部分,在未来城市建设中担任着重要的角色。文章分析杭州城市地下空间(地下交通设施、地下综合体、地下市政设施、人防设施)发展的特点。从开发总量与人均水平、空间分布与开发深度、开发功能3个方面介绍杭州市地下空间开发利用的现状,分析其存在的问题主要为政策及管理方面与功能开发方面。同时介绍未来杭州地下城的发展策略,并展望其发展蓝图。最后分析杭州市地下空间开发建设过程中亟待思考与解决的工程技术问题,包括:特殊地质及工程技术问题(粉土、粉砂地层,淤泥地层,上软下硬地层等问题;近接施工技术,地下立交技术等)、地下工程防灾问题、景区环境保护问题、地下空间全生命周期数字化工程。