苏州地铁四号线近接既有隧道的风险评价研究

为保证近接施工安全,该文以苏州地铁四号线近接既有文陵隧道为工程实例背景,开展了近接施工风险评价研究,即先采用层次分析法构建近接施工风险评价体系,再分别利用1～9标度法和模糊理论确定风险指标的权值和隶属度,以实现近接施工风险等级划分。实例研究表明:各级指标的风险等级分布具有一定差异,但均以三级风险分布相对最多,且近接文陵隧道施工的整体风险得分为66. 09,也属三级风险,进而整体评价本次近接施工过程存在一定风险,但风险等级相对较低,不过仍需采取一定的预防措施,以保证施工安全。通过本文研究,有效掌握了近接施工的风险等级,可有效指导现场施工,也为类似工程的风险评价积累了经验,值得进一步推广应用研究。     

施工风险预警技术在隧道工程中的应用研究

文章通过分析施工现场环境、施工方法和施工机械设备等隧道工程常见的风险因素,提出了基于聚类分析策略的施工风险预警系统,阐述了该预警系统的核心功能,搭建了风险预警模型进行风险数值模拟分析,并结合隧道工程案例,对施工风险预警技术的应用情况进行可靠性评估,证明了所研究内容的合理性。     

城区近距离多孔隧道施工关键技术研究

文章以广州地铁5、6号线区庄换乘地铁车站交叠段近接4孔隧道施工为背景,分析了近接隧道施工过程中地层应力重分布特性,对近接隧道施工中先后施工隧道间的围岩稳定性、隧道支护结构的内力、变形相互影响进行了分析研究,提出了相应的施工安全控制指标;对4孔近接隧道施工中的关键施工力学问题进行了三维模拟计算分析,提出了合理的4孔近接隧道同时施工关键技术方案。研究结果表明,在该地层条件下只要采取合理的地层加固措施和隧道支护方案,合理控制平行近接隧道、空间交叠隧道间的错距,则多孔近接隧道同时施工方案是可行和安全的。     

隧道改扩建工程施工风险评估研究

为研究既有隧道原位改扩建工程施工过程中的风险,以山东淄博淄川区黑峪隧道改扩建工程为例,建立新的隧道改扩建工程施工安全总体风险评估表,评估该工程总体风险属于Ⅳ级极高风险。综合核对表法和专家调查法进行危险源普查,识别出六项重大危险源,并对重大风险进行专项评估。以塌方风险为例,结合隧道改扩建项目施工难度和支护方法,从超前管棚支护、既有隧道洞口加固、新旧隧道交叉处围岩级别、新旧隧道交叉处施工支护方法等多个因子考虑,对塌方风险源进行指标体系法评估。并从支护、爆破、加固、其它施工措施四个方面制定风险消减措施,预防隧道塌方事故。     

肯特指数法在高速公路隧道中的安全风险评估

影响公路隧道施工的风险因素有很多,且这些风险因素具有随机性、不确定性和模糊性,需要进行安全风险评估。文章以广西某高速公路隧道为研究对象,根据安全评价的原则和要求,从几种常用的风险评价方法中选择肯特指数法对该高速公路隧道进行安全风险评估。评估结果表明:该高速公路隧道属于可接受风险水平,与现场情况基本吻合,验证了肯特指数法可以很好地用于高速公路隧道施工安全风险评估。     

地铁区间盾构隧道对周边建筑物结构基础影响分析

针对区间新建隧道近接既有桩基的地铁工程,进行了三维有限元数值模拟的施工力学行为研究.研究结果表明与无桩情况相比较,近接桩基施工将引起新建隧道自身结构,特别是与既有桩基近接一侧边墙,不利的受力特征,并且近接施工还将引起既有桩基产生偏向隧道水平方向的"拉伸"变形情况.因此,需要采取加固措施,以确保隧道自身结构以及近接地下建筑物的安全.此外,考察不同刚度折减系数时,发现桩基水平侧向变形几乎没有变化,这表明改变盾构管片的拼装方式,在整体上对近接地下建筑物几乎无影响.     

盾构隧道基础上修建三条平行隧道地铁车站的施工力学行为研究

结合我国地铁区间单线盾构隧道直径6m左右的实情,提出了在盾构隧道的基础上修建三条平行隧道岛式站台车站方案.对该车站结构的施工力学行为进行了二维有限元数值模拟分析,得出了车站主体结构在施作过程中的受力特征,并对其施工安全性作出了评价,最后提出了相应的设计和施工方面的建议.本研究成果可为今后实际工程的设计和施工提供参考.     

双线盾构隧道近接下穿既有隧道结构沉降变形与施工节点控制分析

城市新建地铁隧道穿越引起既有隧道变形的规律是工程领域研究的热点。文章依托某新建盾构隧道近接下穿既有盾构隧道工程,对施工全过程的实测数据进行整理,结合数值模型计算结果,重点分析了新建左、右线依次穿越过程中既有双线隧道沉降变形规律,进一步对阶段受扰动土体稳定性进行分析。结果表明:(1)时间维度上,穿越过程中既有结构竖向变形趋势与施工阶段具有一一对应关系;(2)距离维度上,隧道结构变形随着距穿越中心距离减小而增大,规律与模拟结果一致;(3)根据既有隧道变形量及变形速率,穿越开始阶段可作为沉降控制的关键节点;(4)既有隧道穿越中心区域沉降量远小于模拟值,实际沉降变形实现重新分布,验证了施工关键节点控制的有效性和结论的准确性。     

两种高架桥T梁现浇施工方法对下穿既有明洞影响研究

高架桥跨越既有铁路隧道明洞施工具有典型的近接工程特征,高架桥施工过程对围岩产生应力重分布,尤其是T梁现浇施工时会对明洞产生附加荷载,对既有隧道衬砌结构轴力、弯矩等内力分布状况产生影响,进而影响结构的安全性。文章依托贵阳至都匀高速公路心焦坡桥跨越黔桂铁路摆梭隧道明洞工程项目,结合ANSYS有限元数值模拟和工法分析,对满堂支架、下设条形基础和梁柱支架跨越隧道两种施工方法进行了分析比较,评估近接施工对下穿明洞安全性的影响,并得出结论:两种方案的明洞素混凝土结构的最小安全系数分别为3.1和3.7,从经济因素考虑满堂支架、下设条形基础方案更有优势。     

地铁零距离穿越工程安全精细控制技术及应用

在城市环境条件下,近接地铁建筑结构工程建设时会受新建地铁结构和已有建筑结构之间的相对位置、其各自的埋深、施工工艺、当地的水文地质等因素影响,新建地铁主要通过施工时控制相关敏感参数来确保近接建筑结构安全。本文依托深圳地铁7号线皇福区间隧洞"零距离"下穿既有4号线福民站的近接工程,综合运用风险评估和数值仿真技术作为控制方法,采用"全断面注浆+CRD平顶直墙暗挖"的施工技术,通过组合工艺综合控制,提出了地铁近接建筑结构工程安全精细控制技术,为城市地铁近接工程的建设与设计提供了重要参考依据。     

An integrated risk assessment model: A case of sustainable freight transportation systems

The major challenge in the development of sustainable freight transportation systems (SFTSs) is due to the involvement of numerous dynamic uncertainties and intrinsic sustainability risks. Sustainability risks are potential threats that can have undesirable impacts on the sustainability of a system. The main objective of this study is to identify and evaluate the sustainability risks associated with freight transportation systems (FTSs). Accordingly, a risk analysis approach is developed by innovatively integrating the intuitionistic fuzzy set theory and D-number theory to quantitatively model the sustainability risks. Intuitionistic fuzzy numbers can examine both the membership and non-membership degrees of an element while the D-number theory increases the objectivity of assessments by fusing multiple expert judgments. The proposed risk assessment model facilitates the managers in the development of SFTSs by ensuring visibility, predictability and measurability in freight operations. Unlike the conventional perception, the findings indicate that most of the high priority sustainability risks in FTSs are socially induced rather than financially driven and consciousness in people’s conduct is must to attain the positive results. The analysis alerts the freight managers toward the high priority sustainability risks and guides in pro-active strategy formulation and optimum allocation of mitigation resources to minimize disruptions in SFTSs.     

轨道交通风险评估WBS工程结构分解准则研究

当前国内轨道交通工程风险评估工作中常用的WBS-RBS风险辨识方法存在不少问题,文章结合工程实践进行了相关研究,明确了工程结构分解法(WBS)的具体分解方法及准则,制定了各分解模块的命名规则.该准则从工程整体上把握风险,遵从风险事件发生特征,避免了传统分类方法存在的重复、不全面等不足;从具体操作流程和分析实例来看,达到了当前风险辨识的目的和风险管控的要求.     

The interaction between road traffic safety and the condition of sewers laid under roads

The main objective of this paper is to show how the service condition of the underground pipeline infrastructure, especially sewage systems, may contribute to road surface failures such as subsidence, bulging and particularly collapse. The analysis was based on CCTV surveys conducted in Poland to investigate the causes of more than a hundred road surface collapse incidents.The method proposed in this paper enables us to determine the risk of road surface collapse as the product of the category of probability of road collapse caused by damaged sewer pipelines and the weighted arithmetic mean category of their consequences.The key conclusions highlight the causes of road collapse incidents, the scale of the hazards, and the benefits resulting from the application of the proposed method to prioritize roads according to the road collapse risk.     

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.     

Infrastructure based approach for roadway departure risk assessment

This paper presents a warning device to prevent the roadway departure of light vehicles while cornering. The proposed risk assessment methodology is based on recent works from the authors (Rey et al., 2011b,a; Rey, 2010). Given the random variability arising from the driver, the vehicle and the infrastructure at the entrance to the curve, a probabilistic strategy is adopted to assess the roadway departure risk. The infrastructure-based methodology enables the real curve characteristics to be considered and an alarm triggering decision to be made. Two safety criteria are tested and the potential safety benefits of the proposed warning device are evaluated. Contrary to existing roadway departure warning systems, the proposed approach does not require extra equipment for vehicles; it only requires that the measuring and warning devices be part of the road infrastructure, which is a great advantage in terms of economic cost.     

Estimating economic losses of industry clusters due to port disruptions

Seaport operations are highly important for industries which rely heavily on imports and exports. A reliable evaluation of port risks is essential to govern the normal running of seaborne transportation and thus the industrial economies. The occurrence of a breakdown in the trade facilitators, such as ports, will disrupt the smooth flow of supply chains for the industries. The estimation of the economic loss for an industry when a port gets disrupted is a challenging task as the relationship between the port and industry clusters is complex. This study aims to develop a systematic framework for performing economic loss estimation of industry clusters due to port disruptions. The whole risk assessment is split into three stages focusing on the establishment of a network flow model, economic estimations and evaluating risk mitigation strategies. The proposed idea is demonstrated by a case study on Shenzhen port and its related manufacturing industries. A dynamic inventory control strategy used by manufacturers is found to be beneficial for mitigating port disruption risks.     

Risk of increasing temperature due to climate change on high-speed rail network in Spain

With more than 3,200 km of track, the Spanish high-speed rail network is the longest network in Europe and the second largest in the world after China. Due to its geographical location in southern Europe, the entire network is exposed to periods of elevated temperatures that can cause disturbances and severe disruptions such as rail deformation, or in the worst case, lateral track buckling. In this study, the vulnerability of the current Spanish high-speed rail network is analysed in terms of track buckling failures with a Monte Carlo simulation. Downscaled temperature projections from a range of Global Climate Models (GCMs), under three Representative Concentration Pathways (RCP4.5, RCP6.0 and RCP8.5), were forced in a buckling model and particularized for different segments of the network. With that, the proposed methodology provides the number of rail buckles expected per year by assuming current maintenance standards and procedures. The result reveals significant increase in the occurrence of buckling events for future years, mainly in the central and southern areas of mainland Spain. However, relevant variations are found in different climates and time horizon scenarios in Spain. The anticipated buckling occurrences highlight the vulnerability of the Spanish rail network in the context of global warming scenarios. Overall, the proposed methodology is designed to be applicable in large-scale railway networks to identify potential buckling sites for the purpose of understanding and predicting their behaviour.     

A Value-at-Risk (VAR) approach to routing rail hazmat shipments

Hazardous materials (hazmat) accidents are rare though the consequences could be disastrous. Given the possibility of low probability – high consequence event, a risk-averse routing hazmat shipment is necessary. We propose a value-at-risk (VaR) approach to route rail hazmat shipments, using the best train configuration, over a given railroad network with limited number of train services such that the transport risk as measured by VaR is minimized. Freight train derailment reports of the Federal Railroad Administration were analyzed to develop expressions that would incorporate characteristics of railroad accidents, and then to estimate the different inputs. The proposed methodology was used to study several problem instances generated using the realistic network of a railroad operator, and to demonstrate that it is possible to develop different routes for shipments depending on the risk preference of the decision maker.     

铁路隧道风险评估若干问题探讨

文章探讨了当前隧道风险评估中存在的隧道初始和残余风险综合等级判定准则的不统一、施工阶段风险评估中风险因素的缺失及初步设计阶段风险评估"谈虎色变"、施工阶段风险评估"避轻就重"等问题,提出了解决这些问题的对策,即初始和残余风险综合等级就高准则、隧道施工阶段快速适时风险评估和特殊地区隧道初始风险等级合理确定等。     

复线桥施工对既有桥梁的安全控制分析

在既有桥梁下新建复线桥时,新建桥梁施工过程必然对既有桥梁产生影响。文章以重庆高家花园复线桥主桥为研究对象,分析复线桥主桥基础施工、桥墩施工和主梁施工各个阶段的风险源,并采用风险矩阵分析,合理评估每一风险事态对既有桥梁造成的风险等级,提出风险应对措施,以减少总体风险损失。通过风险评估,可为复线桥施工提供科学依据,杜绝安全隐患与风险,加快施工进度。