铁路隧道工程可行性研究阶段风险评估研究

风险评估对于铁路隧道工程的建设和项目选线具有重要意义。针对铁路隧道工程风险评估在可行性阶段对应的风险类别与风险因素,建立基于AHP法的多因素模糊综合评价体系以及相应的隧道风险等级定量评判标准。模型根据专家对各风险类别和风险因素相对发生概率的定性评判,通过AHP法计算得到各风险类别和风险因素在整个风险评估体系中发生的相对概率,并将风险事件发生后果等级赋予相应的风险分值。最终结合得到的概率与风险分值通过模糊综合评价得到隧道综合风险评估分值和其对应的风险等级,从而对铁路隧道工程风险进行综合、定量、直观的评估。将A隧道运用该体系进行分析评价,得到其在可行性研究阶段的综合风险评估值为4. 774,风险等级为中度。     

南宁地铁2号线岩溶风险分析和处理原则

岩溶地区城市地铁修建过程中,岩溶地质灾害问题严重威胁着地铁施工和后期运营的安全,由于受到地质条件和人类工程活动等多因素影响,需要综合分析各影响因素的作用,进而制定岩溶处理原则。以南宁地铁2号线石子塘车站和石子塘站—大沙田站区间为例,分析岩溶洞穴几何特征以及空间分布规律,针对不同岩溶塌陷风险等级的影响范围和危险程度,确定相应岩溶处理原则。石子塘车站岩溶塌陷可以划分为高风险区、中等风险区、低风险区,其岩溶处理范围分别为隧道轮廓线两侧围护结构处基岩界面以下15、10、6 m,处理措施分别为采用注浆帷幕以及钻孔灌注桩+内支撑体系的围护结构,注浆帷幕以及围护孔和中立柱桩加固,注浆以及围护孔和临时立柱桩。基于不同岩溶塌陷风险等级的岩溶处理原则考虑岩溶场地的复杂性,具有较大实际工程意义,对今后岩溶地区城市隧道的施工有一定参考价值和借鉴意义。     

铁路车务系统既有线施工安全风险管理探讨

针对铁路既有线改造施工、日常养护对运输效率和运输能力的影响,分析既有线施工对车务系统安全风险管理的要求,探讨施工现场车务系统的安全卡控措施,即强化车务系统管理人员的安全责任制和施工安全风险关键点的卡控措施,探索既有线施工安全风险管理的新方法、新途径,逐步形成安全风险管理的长效机制。     

桥梁工程事故回顾分析与对策探讨

本文通过回顾从19世纪初以来世界上主要发生的桥梁事故情况,选取其中三个较为典型的桥梁事故,分析其倒塌的原因,并结合作者收集的信息,统计出桥梁事故发生的规律,从而对避免桥梁工程事故的发生提出一些建议和对策。     

地铁建设工程的风险管理应用研究

地铁建设工程作为一项大型工程项目,往往存在着大量的不确定风险因素,因而风险管理在地铁工程中变得越来越重要.文章通过对国内外地铁工程事故经验的探讨,提出了地铁建设工程中风险管理的框架,包括风险辨识、分析和评估、应对以及风险防范措施等,以预防和减轻地铁工程风险,达到降低风险等级的目的.     

Collision course? The North Airfield Safety Study at Los Angeles International Airport (LAX)

The LAX North Airfield Safety Study was undertaken by an Academic Panel consisting of the present authors, and was based in large part on a simulation that was conducted at FutureFlight Central at NASA Ames Research Center. The primary aim of the study was “to estimate as specifically as possible the level of future safety associated with several geometrical configurations of the LAX North Airfield.” This paper describes the study, and how it combined information from human-in-the-loop simulations at NASA with historical data from LAX and other US airports about runway incursions and collisions. The analysis indicated that, even under its existing physical layout, LAX North would experience very low risk of runway collisions at traffic levels projected for 2020. That risk could be reduced by about half if the North Airfield runways were reconfigured, and some reconfigurations would also add appreciably to the operational efficiency of the airport. But because the “baseline” level of risk is so low, the Study concluded that “it would be difficult to construct a compelling case on safety grounds alone for reconfiguring the North Airfield.”     

山区公路地质灾害评价模型探讨

目前对公路沿线地质灾害的评价方法以定性评价为主,尚未形成一套行之有效的定量或半定量评价体系和方法。文章根据公路工程的特点以及现有的地质灾害评估理论和实践,并结合公路地质灾害野外调查情况,提出了公路地质灾害发育程度、危害性、发展趋势及危险性评价方法,可供有关部门参考。     

Modeling heterogeneous risk-taking behavior in route choice: A stochastic dominance approach

This paper proposes a unified approach to modeling heterogonous risk-taking behavior in route choice based on the theory of stochastic dominance (SD). Specifically, the first-, second-, and third-order stochastic dominance (FSD, SSD, TSD) are respectively linked to insatiability, risk-aversion and ruin-aversion within the framework of utility maximization. The paths that may be selected by travelers of different risk-taking preferences can be obtained from the corresponding SD-admissible paths, which can be generated using general dynamic programming. This paper also analyzes the relationship between the SD-based approach and other route choice models that consider risk-taking behavior. These route choice models employ a variety of reliability indexes, which often make the problem of finding optimal paths intractable. We show that the optimal paths with respect to these reliability indexes often belong to one of the three SD-admissible path sets. This finding offers not only an interpretation of risk-taking behavior consistent with the SD theory for these route choice models, but also a unified and computationally viable solution approach through SD-admissible path sets, which are usually small and can be generated without having to enumerate all paths. A generic label-correcting algorithm is proposed to generate FSD-, SSD-, and TSD-admissible paths, and numerical experiments are conducted to test the algorithm and to verify the analytical results.     

基于故障树的动车组常用制动失效风险分析及对策

分析CRH3型动车组制动系统的工作原理、结构、功能及工作流程,根据其关键功能,包括空电复合制动、网络和硬线冗余指令传递、直通式电空制动方式、电气指令和空气指令传输方式等的特点,对常用制动系统结构和功能进行分解,建立常用制动失效故障树,分析基本事件的结构重要度,得出牵引执行系统电机故障、牵引控制单元故障、网压过高是导致常用制动失效发生的最重要因素,提出针对各类基本原因事件的风险控制措施.     

A trial application of FSA methodology to the hatchway watertight integrity of bulk carriers

Formal safety assessment (FSA) is a formal, structured and systematic methodology, aimed at enhancing maritime safety, including protection of life, property and marine environment, by using risk and cost–benefit assessments. For the application of this methodology to the rule-making process, the International Maritime Organization (IMO) presented the Interim Guidelines, which describe procedures of FSA and inputs/outputs of each procedure in detail. This paper basically deals with an application of FSA methodology according to the IMO's Interim Guidelines to the hatchway watertight integrity of bulk carriers, which was carried out as a cooperative research between Korean Register of Shipping and Seoul National University. As results of this application study, 18 hazards are identified and 32 risk control measures are devised to reduce the associated risks. Potential risks, costs and benefits when some Risk Control Options are introduced are evaluated in monetary unit of US $. Finally, some discussions and recommendations based on experiences are also given for both future work and better application of this FSA methodology to the rule-making process.