基于事故树分析法的控制爆破危害影响研究

广西河百高速在施工过程中部分开挖路段需进行爆破开挖,周边有居民房,为确保施工安全,需控制爆破冲击波、爆破振动和爆破飞石等对人员和构筑物的不利影响。采用安全系统工程中事故树分析方法对危险因素展开了系统分析,分别建立了爆破冲击波、爆破振动和爆破飞石事故树,综合分析得到事故树最小割集、事故树最小径集和事故树结构重要度,指出各个因素主次。结果表明:综合爆破冲击波、爆破振动和爆破飞石的事故树分析,在爆破施工过程中要加大施工现场监管、施工设计、减振措施和爆破警戒范围内飞石控制措施等的管理力度。     

基于事件树分析法的大跨斜拉桥施工事故分析

以宁波招宝山大桥为研究背景,以其在建设过程中发生的主梁压溃事故原因分析为目标,提出应用事件树分析法对该桥梁施工事故进行仿真反演分析。具体步骤为,应用事件树分析法对所有可能事故原因进行定性分析,确定事故分析方案;应用仿真反演技术对事故分析方案进行定量仿真计算,反演出事故的真正原因和机理。计算分析表明该桥梁施工事故可能是三种原因共同作用的结果。其中,斜拉索局部超张拉是事故主要原因,底板厚度不足和脉动风对该事故也有一定的影响。分析结果表明:事件树分析法使得事故分析更为系统、全面。     

计算机辅助事故树绘图研究

实现计算机辅助事故树绘图是计算机辅助事故树绘图是计算机辅助事故树分析中的重要组成部分。本文给出了两种实用的计算机辅助事故绘图方法,即“堆砖法”和“控制点法”。而后者由于真正实现了交互式绘图,解决了事故数据的自动采集和处理,因而实际上也是事故树的一种数据输入法,即由图形得到事故树全部数据的图形输入法。文中对这两种方法的算法进行了详细描述,这两种思想和算法不仅解决了事故树的实际绘制问题,而且对绘制其它类型的树及图将大有益处。     

基于可视化的事故树分析系统研究与开发

事故树分析是安全系统工程最重要的分析方法之一，它能对各种系统的危险性进行辨识和评价，不仅能分析出事故的直接原因，而且能深入地揭示出事故的潜在原因。用它描述事故的因果关系直观、明了，思路清晰，逻辑性强，既可定性分析，又可定量分析。基于可视化理论和技术，建立了事故树可视化模型，确定了系统功能目标，完成了系统结构设计，构造了事故树图形生成与事故树动态分析于一体的集成分析环境，开发出事故树计算机分析系统，为事故分析和安全评价提供高效、准确的技术和方法。     

事故树分析在电梯检测中的应用

本文介绍电梯各机构系统的特点,对电梯整体进行简要的安全评价,为电梯安全方面的决策提供方法。并通过讨论事故树分析,指出了事故树在电梯检测中的应用。结合电梯事故的实例,分析了事故树的编制,得出引发改事故的原因。     

事故树图形的计算机辅助绘制算法研究

提供了一种有效的算法,根据输入的各种事件的基本信息及其因果逻辑关系,利用树的深度优先遍历后序算法,实现事故树的自动绘制,体现事故树模型分析形象、直观、明了的特点.该算法能即时计算出事故树顶事件发生的概率、最小割集、概率重要度、关键重要度等参数,为对事故树进行定性、定量分析提供强有力的图形和数据支持.     

一起门式起重机倒塌事故分析与思考

门式起重机在各类生产企业使用很多,用途很广,在安装使用的过程中安全事故时有发生,特别是安装过程中,尤其特别危险,本文通过一起安装过程中门式起重机倾覆事故的原因进行分析,查找出事故发生的原因,提出加强制造单位的制造质量,强化使用单位严格执行安全使用管理规则,强化安装单位施工安全管理,有利于减少同类事故的发生。     

爆破的事故树分析

事故树分析在当前的系统安全工程安全性分析和评估方面的应用引人注目。本文简要叙述了事故树分析的意义,事故调查方法以及爆破的事故树编制实例。     

液氧贮槽爆炸事故树分析

采用安全系统工程的方法 ,对液氧贮槽爆炸进行了事故树分析 ,通过求事故树最小割集 ,进行结构重要度分析 ,从而对液氧贮槽爆炸的事故原因进行分析、预测 ,并提出了相应的预防控制措施     

基于事故树的煤矿安全预警管理模型探讨

根据事故树分析原理,分析研究煤矿安全生产现状,建立煤矿安全事故的影响模型,对降低我国煤矿安全事故发生率,促进煤矿安全可持续发展具有重要的现实意义,瓦斯事故是煤矿生产以及洗选过程中常见的事故之一,以瓦斯事故为例,介绍事故树分析法在实际中的应用。     

Analysis of large fault trees based on functional decomposition

With the advent of the Binary Decision Diagrams (BDD) approach in fault tree analysis, a significant enhancement has been achieved with respect to previous approaches, both in terms of efficiency and accuracy of the overall outcome of the analysis. However, the exponential increase of the number of nodes with the complexity of the fault tree may prevent the construction of the BDD. In these cases, the only way to complete the analysis is to reduce the complexity of the BDD by applying the truncation technique, which nevertheless implies the problem of estimating the truncation error or upper and lower bounds of the top-event unavailability.This paper describes a new method to analyze large coherent fault trees which can be advantageously applied when the working memory is not sufficient to construct the BDD. It is based on the decomposition of the fault tree into simpler disjoint fault trees containing a lower number of variables. The analysis of each simple fault tree is performed by using all the computational resources. The results from the analysis of all simpler fault trees are re-combined to obtain the results for the original fault tree.Two decomposition methods are herewith described: the first aims at determining the minimal cut sets (MCS) and the upper and lower bounds of the top-event unavailability; the second can be applied to determine the exact value of the top-event unavailability. Potentialities, limitations and possible variations of these methods will be discussed with reference to the results of their application to some complex fault trees.     

SMV model-based safety analysis of software requirements

Fault tree analysis (FTA) is one of the most frequently applied safety analysis techniques when developing safety-critical industrial systems such as software-based emergency shutdown systems of nuclear power plants and has been used for safety analysis of software requirements in the nuclear industry. However, the conventional method for safety analysis of software requirements has several problems in terms of correctness and efficiency; the fault tree generated from natural language specifications may contain flaws or errors while the manual work of safety verification is very labor-intensive and time-consuming. In this paper, we propose a new approach to resolve problems of the conventional method; we generate a fault tree from a symbolic model verifier (SMV) model, not from natural language specifications, and verify safety properties automatically, not manually, by a model checker SMV. To demonstrate the feasibility of this approach, we applied it to shutdown system 2 (SDS2) of Wolsong nuclear power plant (NPP). In spite of subtle ambiguities present in the approach, the results of this case study demonstrate its overall feasibility and effectiveness.     

露天深孔爆破导爆管起爆网路盲炮事故树分析

为避免露天深孔爆破导爆管起爆网路产生盲炮,确保爆破施工安全,按照露天深孔爆破作业流程,通过分析导爆管起爆网路盲炮产生原因,建立了事故树模型。并在此基础上进行了定性分析,求出事故树最小割集为32个,最小径集为4个。得到了结构重要度排序,提出了盲炮事故预防的对策措施,可为类似工程的爆破设计、施工和安全管理提供参考。     

Systematic evaluation of fault trees using real-time model checker UPPAAL

Fault tree analysis, the most widely used safety analysis technique in industry, is often applied manually. Although techniques such as cutset analysis or probabilistic analysis can be applied on the fault tree to derive further insights, they are inadequate in locating flaws when failure modes in fault tree nodes are incorrectly identified or when causal relationships among failure modes are inaccurately specified. In this paper, we demonstrate that model checking technique is a powerful tool that can formally validate the accuracy of fault trees. We used a real-time model checker UPPAAL because the system we used as the case study, nuclear power emergency shutdown software named Wolsong SDS2, has real-time requirements. By translating functional requirements written in SCR-style tabular notation into timed automata, two types of properties were verified: (1) if failure mode described in a fault tree node is consistent with the system's behavioral model; and (2) whether or not a fault tree node has been accurately decomposed. A group of domain engineers with detailed technical knowledge of Wolsong SDS2 and safety analysis techniques developed fault tree used in the case study. However, model checking technique detected subtle ambiguities present in the fault tree.     

故障树分析法在乳化炸药生产中的应用概述

乳化炸药生产线的故障诊断问题一直是乳化炸药安全领域十分必要且有意义的课题。文章提出以故障模式及影响分析为基础的故障树分析法,并应用于乳化炸药的生产过程中。这种方法不仅可以对造成乳化炸药产品质量不合格的原因进行定性分析和定量分析,还可以通过分析这些原因,对生产过程中存在的潜在问题加以解决。     

Identification of independent modules in fault trees which contain dependent basic events

The reliability performance of a system is frequently a function of component failures of which some are independent whilst others are interdependent. It is possible to represent the system failure logic in a fault tree diagram, however only the sections containing independent events can be assessed using the conventional fault tree analysis methodology. The analysis of the dependent sections will require a Markov analysis. Since the efficiency of the Markov analysis largely depends on the size of the established Markov model, the key is to extract from the fault tree the smallest sections which contain dependencies. This paper proposes a method aimed at establishing the smallest Markov model for the dependencies contained within the fault tree.     

Component-based modeling of systems for automated fault tree generation

One of the challenges in the field of automated fault tree construction is to find an efficient modeling approach that can support modeling of different types of systems without ignoring any necessary details. In this paper, we are going to represent a new system of modeling approach for computer-aided fault tree generation. In this method, every system model is composed of some components and different types of flows propagating through them. Each component has a function table that describes its input-output relations. For the components having different operational states, there is also a state transition table. Each component can communicate with other components in the system only through its inputs and outputs. A trace-back algorithm is proposed that can be applied to the system model to generate the required fault trees. The system modeling approach and the fault tree construction algorithm are applied to a fire sprinkler system and the results are presented.     

Gastric esophageal surgery risk analysis with a fault tree and Markov integrated model

Reliability methods have been widely used in risk analysis of medical surgeries. In this study, the authors combine a fault tree with Markov models to assess time independent- and dependent factors together. Dynamics are integrated in the traditional fault tree, and meanwhile the processes of solving Markov are simplified with the modular approach. Continuous time Markov chains are adopted in evaluating the failure probability of a gastric esophageal surgery after categorizing basic events in the fault tree, and a certain time dependent variables, such as failure rate of medical equipment, surgery frequency, and rescue timeliness are involved into risk analysis. A case is studied with data collected from a general hospital, to illustrate the operational process of the proposed method. Results based on the inputs show that taking rescue actions into consideration can reduce the gap between the result of fault tree analysis and the reality. Sensitivity analysis for measuring the impacts of the above time relevant variables is conducted, as well as limitations of the Markov model are discussed.     

Computer-aided fault tree synthesis III: Real-time fault location

This paper is devoted to fault tree synthesis and is split up into three parts. Part I starts with the introduction of component models that show all fault propagation through the components and fault initiation by the components in both directions (upstream and downstream). Subsequently, it is shown how to create system models that interconnect a system's components and environmental variables. Then a fault tree construction algorithm is introduced which is able to generate fault trees from the given system and component models in two steps. First a causal tree is constructed showing the propagation paths for all basic events leading to any deviation in the top parameter. All control loops (feedback and feedforward loops) in this causal tree must be traced prior to any fault tree construction since they might prevent some faults from reaching the top parameter. They consequently require a special treatment. Part I ends showing how to adapt the causal trees for these loops. Part II discusses the final step of the fault tree construction algorithm, i.e. it shows how fault trees can be abstracted from the causal diagram, and ends with a comprehensive example. Finally, Part III discusses a method for real-time fault location which is based on the causal tree construction procedure introduced in Part I.