Multi-Hazard Evaluation Using Cluster Analysis—For Designated Evacuation Centers of Yokohama

Hazard maps are usually prepared for each disaster, including seismic hazard maps, flood hazard maps, and landslide hazard maps. However, when the general public attempts to check their own disaster risk, most are likely not aware of the specific types of disaster. So, first of all, we need to know what kinds of hazards are important. However, the information that integrates multiple hazards is not well maintained, and there are few such studies. On the other hand, in Japan, a lot of hazard information is being released on the Internet. So, we summarized and assessed hazard data that can be accessed online regarding shelters (where evacuees live during disasters) and their catchments (areas assigned to each shelter) in Yokohama City, Kanagawa Prefecture. Based on the results, we investigated whether a grouping by cluster analysis would allow for multi-hazard assessment. We used four natural disasters (seismic, flood, tsunami, sediment disaster) and six parameters of other population and senior population. However, since the characteristics of the population and the senior population were almost the same, only population data was used in the final examination. From the cluster analysis, it was found that it is appropriate to group the designated evacuation centers in Yokohama City into six groups. In addition, each of the six groups was found to have explainable characteristics, confirming the effectiveness of multi-hazard creation using cluster analysis. For example, we divided, all hazards are low, both flood and Seismic hazards are high, sediment hazards are high, etc. In many Japanese cities, disaster prevention measures have been constructed in consideration of ground hazards, mainly for earthquake disasters. In this paper, we confirmed the consistency between the evaluation results of the multi-hazard evaluated here and the existing ground hazard map and examined the usefulness of the designated evacuation center. Finally, the validity was confirmed by comparing this result with the ground hazard based on the actual measurement by the past research. In places where the seismic hazard is large, the two are consistent with the fact that the easiness of shaking by actual measurement is also large.

Multi-hazard performance assessment of a transfer-plate high-rise building

Many urban areas are located in regions of moderate seismicity and are subjected to strong wind. Buildings in these regions are often designed without seismic provisions. As a result, in the event of an earthquake, the potential for damage and loss of lives may not be known. In this paper, the performance of a typical high-rise building with a thick transfer plate （TP）, which is one type of building structure commonly found in Hong Kong, is assessed against both earthquake and wind hazards. Seismic- and wind-resistant performance objectives are first reviewed based on relevant codes and design guidelines for high-rise buildings. After a brief introduction of wind-resistant design of the building, various methodologies, including equivalent static load analysis （ESLA）, response spectrum analysis （RSA）, pushover analysis （POA）, linear and nonlinear time-history analysis （LTHA and NTHA）, are employed to assess the seismic performance of the building when subjected to frequent earthquakes, design based earthquakes and maximum credible earthquakes. The effects of design wind and seismic action with a common 50-year return period are also compared. The results indicate that most performance objectives can be satisfied by the building, but there are some objectives, such as inter-story drift ratio, that cannot be achieved when subjected to the frequent earthquakes. It is concluded that in addition to wind, seismic action may need to be explicitly considered in the design of buildings in regions of moderate seismicity.

Towards establishing practical multi-hazard bridge design limit states

In the U.S., the current Load and Resistance Factor Design （LRFD） Specifications for highway bridges is a reliability-based formulation that considers failure probabilities of bridge components due to the actions of typical dead load and frequent vehicular loads. Various extreme load effects, such as earthquake and vessel collision, are on the same reliability-based platform. Since these extreme loads are time variables, combining them with not considered frequent. non- extreme loads is a significant challenge. The number of design limit state equations based on these failure probabilities can be unrealistically large and unnecessary from the view point of practical applications. Based on the opinion of AASHTO State Bridge Engineers, many load combinations are insignificant in their states. This paper describes the formulation of a criterion to include only the necessary load combinations to establish the design limit states. This criterion is established by examining the total failure probabilities for all possible time-invariant and time varying load combinations and breaking them down into partial terms. Then, important load combinations can be readily determined quantitatively,

山区公路桥梁多灾害联合作用数值模拟

山区公路桥梁长期遭受冲刷及磨蚀等水文灾害,期间可能同时伴随崩塌落石等地质灾害的作用.为探明多灾害作用下山区公路桥梁的结构响应及损伤机理,从流固耦合的角度出发,针对冲刷及磨蚀的数据传递推导相应的插值算法,并结合生死单元功能,构建基于Delaunay三角剖分及特征点协同插值的山区公路桥梁多灾害联合作用数值仿真方法.首先,针对冲刷数据,基于三角形内部插值理论构建冲刷数据传递方程.其次,针对磨蚀/波流力数据,基于三维表面Delaunay三角剖分及三角形外部插值理论补充推导数据传递方程,再利用特征点协同插值算法计算结构域目标单元总结果.最后,基于生死单元功能,在结构域中考虑冲刷坑及桩基磨蚀形态,构建冲刷及磨蚀条件下落石冲击山区公路桥梁墩柱数值模型.结果表明:所采用的针对冲刷及磨蚀模型数据的插值方法精度较高;在不同的冲击速度、冲击角度及落石质量工况下,与无冲刷磨蚀相比,冲刷、冲刷磨蚀条件下桥墩冲击力峰值的相对变化呈现非线性特征,此外,在冲刷条件下,桩基磨蚀对冲击力峰值亦产生非线性影响;随着冲击速度及落石质量的增大,各条件下冲击点位移峰值均变大,且位移峰值从大到小均依次为冲刷、冲刷磨蚀和无冲刷磨蚀,同时在各冲击速度、冲击角度及落石质量工况下,磨蚀引起的位移峰值最大降幅分别约为2%、11%及4%.

基于Multi-Agent的机场安全风险管理模型研究

为了能够实时监控危险源,提高风险评价和风险控制的有效性,本文基于理性Agent的BDI模型,引入多Agent组的概念,采用结果共享通信模型作为多Agent通信求解方法,构建了基于Multi-Agent的安全风险管理模型,并对模型中各组成部分的结构和功能进行了定义和说明。最后,以某机场飞行区不停航施工为例,将基于MAS的安全风险管理模型应用于机场安全风险管理中,结果表明该模型能够对风险进行实时监控,并进行有效控制。该研究可为机场安全风险管理提供新的思路。

Bridge pier failure probabilities under combined hazard effects of scour, truck and earthquake. Part Ⅰ: occurrence probabilities

In many regions of the world, a bridge will experience multiple extreme hazards during its expected service life. The current American Association of State Highway and Transportation Officials （AASHTO） load and resistance factor design （LRFD） specifications are formulated based on failure probabilities, which are fully calibrated for dead load and nonextreme live loads. Design against earthquake loads is established separately. Design against scour effect is also formulated separately by using the concept of capacity reduction （or increased scour depth）. Furthermore, scour effect cannot be linked directly to an LRFD limit state equation, because the latter is formulated using force-based analysis. This paper （in two parts） presents a probability-based procedure to estimate the combined hazard effects on bridges due to truck, earthquake and scour, by treating the effect of scour as an equivalent load effect so that it can be included in reliability-based bridge failure calculations. In Part I of this series, the general principle of treating the scour depth as an equivalent load effect is presented. The individual and combined partial failure probabilities due to truck, earthquake and scour effects are described. To explain the method of including non-force-based natural hazards effects, two types of common scour failures are considered. In Part 11, the corresponding bridge failure probability, the occurrence of scour as well as simultaneously having both truck load and equivalent scour load are quantitatively discussed.

Bridge pier failure probabilities under combined hazard effects of scour, truck and earthquake. Part Ⅱ: failure probabilities

In many regions of the world, a bridge will experience multiple extreme hazards during its expected service life. The current American Association of State Highway and Transportation Officials （AASHTO） load and resistance factor design （LRFD） specifications are formulated based on failure probabilities, which are fully calibrated for dead load and non-extreme live loads. Design against earthquake load effect is established separately. Design against scour effect is also formulated separately by using the concept of capacity reduction （or increased scour depth）. Furthermore, scour effect cannot be linked directly to an LRFD limit state equation because the latter is formulated using force-based analysis. This paper （in two parts） presents a probability-based procedure to estimate the combined hazard effects on bridges due to truck, earthquake and scour, by treating the effect of scour as an equivalent load effect so that it can be included in reliability-based failure calculations. In Part I of this series, the general principle for treating the scour depth as an equivalent load effect is presented. In Part II, the corresponding bridge failure probability, the occurrence of scour as well as simultaneously having both truck load and equivalent scour load effect are quantitatively discussed. The key formulae of the conditional partial failure probabilities and the necessary conditions are established. In order to illustrate the methodology, an example of dead, truck, earthquake and scour effects on a simple bridge pile foundation is represented.

Seismic fragility analysis of highway bridges considering multi-dimensional performance limit state

Fragility analysis for highway bridges has become increasingly important in the risk assessment of highway transportation networks exposed to seismic hazards. This study introduces a methodology to calculate fragility that considers multi-dimensional performance limit state parameters and makes a first attempt to develop fragility curves for a multi-span continuous (MSC) concrete girder bridge considering two performance limit state parameters: column ductility and transverse deformation in the abutments. The main purpose of this paper is to show that the performance limit states, which are compared with the seismic response parameters in the calculation of fragility, should be properly modeled as randomly interdependent variables instead of deterministic quantities. The sensitivity of fragility curves is also investigated when the dependency between the limit states is different. The results indicate that the proposed method can be used to describe the vulnerable behavior of bridges which are sensitive to multiple response parameters and that the fragility information generated by this method will be more reliable and likely to be implemented into transportation network loss estimation.

Disaster reduction stick equipment: A method for monitoring and early warning of pipeline-landslide hazards

Oil and gas pipelines are of great importance in China,and pipeline security problems pose a serious threat to society and the environment.Pipeline safety has therefore become an integral part of the entire national economy.Landslides are the most harmful type of pipeline accident,and have directed increasing public attention to safety issues.Although some useful results have been obtained in the investigation and prevention of pipeline-landslide hazards,there remains a need for effective monitoring and early warning methods,especially when the complexity of pipeline-landslides is considered.Because oil and gas pipeline-landslides typically occur in the superficial soil layers,monitoring instruments must be easy to install and must cause minimal disturbance to the surrounding soil and pipeline.To address the particular characteristics of pipelinelandslides,we developed a multi-parameter integrated monitoring system called disaster reduction stick equipment.In this paper,we detail this monitoring and early warning system for pipeline-landslide hazards based on an on-site monitoring network and early warning algorithms.The functionality of our system was verified by its successful application to the Chongqing Loujiazhuang pipeline-landslide in China.The results presented here provide guidelines for the monitoring,early warning,and prevention of pipeline geological hazards.

地震和风耦合作用下超高层连体结构易损性分析

为探究超高层连体结构在多灾害耦合作用下的设计与安全性能,以苏州超塔为例,开展地震和风耦合作用下的多灾害易损性分析.根据设计资料建立结构有限元模型,分别开展结构在地震作用下以及地震和风耦合作用下的易损性分析,探究结构在多灾害耦合作用下的响应规律.结果表明,地震和风耦合作用下结构联合易损性随着地震动和风荷载强度的增大而增加,且地震动对结构的破坏占主导作用.地震与风耦合作用时结构达到中等破坏、严重破坏和倒塌破坏的概率均比仅地震作用时有所增加.当风速达到40 m/s时,结构在罕遇地震下达到3种破坏状态的概率分别为99.77%、91.56%和46.54%,相比于仅罕遇地震作用下分别提高了1.11%、10.73%和14.65%,相比于一般高层连体结构在同样的灾害耦合作用下分别提高了0.27%、6.26%和14.34%.

西部矿区采动损害及减损开采的地质保障技术框架体系

【目的】煤炭在我国的主体能源地位短期内难以发生改变,是我国能源发展的兜底保障。煤炭资源大规模、高强度的开采损害煤矿区地质环境,同时导致突水、冲击地压等灾害。【方法】围绕煤矿安全高效开采面临的地质环境损害预测预警难和减损开采保障压力大等难题,基于煤炭采动损害预测与减损地质保障多学科交叉特点,突出地质条件的控灾机理和采动致灾模式,强调煤炭开采模式与地质结构演化全时空多场响应,分析采动效应下地质条件物质场、能量场、信息场的耦合机制,厘清损害模式和预警信息关键参量的映射关系,形成安全高效开采的地质保障策略和减损控灾工程技术体系。【结果和结论】研究思路为“孕灾环境→损害机制→过程响应→损害预测→防灾减损”,技术路线是“煤矿开采地质环境条件→地质结构演化规律及损害模式→多物理场演化全时空信息响应→损害监测及预测预警→减损保障工程技术”。核心内容包括:(1)剖析地质条件与致灾地质体的空间关系和成因联系,构建高精度的三维地质力学模型,阐明地质结构、开采条件和损害模式的映射关系,建立主控要素的特征参量数据库;(2)构建采动效应下的工程地质力学模型,研究开采方式、空间布局、采动速率等影响下地质条件结构的时空演化特征和损害机制,提出考虑地质体关键结构破坏演化规律的损害模式判识方法;(3)获取采动过程地质结构演化背景下的全时空多源信息响应,提出主控参量作用下的损害模式识别标准,进而厘清裂隙场、应力场、渗流场与地球物理场信息参量的镜像关系,建立基于地质条件物质场、能量场和信息场耦合响应的全时空信息映射模型;(4)构建地面-钻孔-井下的全空间、多方位、主被动的一体化多源监测体系,提出煤矿采动损害预测模型和预报方法;(5)构建基于损害源、损害模式、损害动力、损害通道剖析以及减损技术与效果评价于一体的减损控灾体系,追求煤炭安全开采与地质环境保护协调发展,破解资源开发与地质环境制约之间的矛盾,为煤矿安全高效开采和防灾减损提供地质、力学、物理基础的科学依据。

滑坡-泥石流灾害链特征分析与风险评价——以川西石棉县马颈子沟为例

我国川西地区地形地貌和地质构造复杂,滑坡-泥石流灾害链易发育,灾害链中主要灾害向次要灾害逐级传递,促使灾害的风险性进一步增强。为研究滑坡-泥石流灾害链的特征与风险性,以四川马颈子沟滑坡-泥石流灾害链为典型研究对象,对该区域滑坡和泥石流分别进行风险度分析,并对区域滑坡-泥石流灾害链进行特征分析与风险评价。首先构建AHP模型对滑坡危险度进行分析,并应用易损性等级计算模型计算滑坡易损性;然后应用泥石流危险区指标来估算泥石流的危险度,并根据区域统计数据得出区域泥石流灾害损失脆弱性;最后根据多灾害风险理论公式,计算区域滑坡-泥石流灾害链风险度,并对灾害链进行风险评价。结果表明:马颈子沟滑坡-泥石流灾害链为中风险度地区,该研究结果与现场勘察结果一致,验证了基于多灾害风险理论的灾害链分析评价方法体系结合多种模型进行计算的可行性。通过分析马颈子沟灾害链风险度,为类似研究提供理论依据。

基于多源数据与机器学习的降雨型滑坡灾害危险性动态预警

降雨型滑坡灾害是三峡库区发育的主要地质灾害之一,区域滑坡灾害危险性预警对滑坡风险减缓有重要意义。针对区域滑坡灾害危险性预警的时效性等问题,本文以重庆市云阳县为研究区,提出了基于多源数据与机器学习的滑坡灾害危险性动态预警方法(图1)。1滑坡易发性空间预测滑坡易发性预测可准确地预测出潜在滑坡空间分布规律(黄发明等,2020;林高聪等,2023)。

自然灾害风险监测框架及产品体系设计

自然灾害风险监测是防灾减灾救灾领域的基础性和前沿性工作,为风险评估、灾害预警和综合减灾提供基础数据和研判信息。自然灾害风险监测当前处于理论研究和业务探索阶段,存在业务服务不精准、产品体系不健全、实践难题未凝练、关键技术未突破和监测站网不完备等难题,还不能满足灾害风险早发现、早识别和早防范的现实需求。结合多灾种灾害链基础理论和业务实践,阐明“为何监测、何时监测、怎么监测、监测哪里、监测什么”等业务系统化、体系化发展思路。为全面提升自然灾害风险监测产品决策支撑能力,设计了包括业务体系构建、关键技术突破、标准规范形成、数据库建设、应用平台开发和典型应用推广等在内的总体框架,构建应用场景、产品类型和产品要素一体化的科学精细的业务产品体系。

热带气旋多致灾因子综合风险评估研究进展

【目的】热带气旋伴随的大风、暴雨及引发的风暴潮、洪涝等致灾因子,为热带气旋风险评估带来了极大的挑战。针对当前热带气旋多致灾因子综合风险评估方法不一的问题,【方法】通过文献分析方法,阐述了热带气旋多致灾因子间的相互关系,并对热带气旋多致灾因子的危险性、承灾体脆弱性和风险评估研究现状进行了梳理。【结果】结果表明:综合考虑热带气旋多因子复合链生关系的定量化风险评估方法极为缺乏,如何降低气候变化背景下未来热带气旋风险评估结果的不确定性是当前的一个难点。【结论】未来可以在厘清热带气旋多致灾因子复杂关系的基础上,基于大数据和机器学习等计算机手段,从机理角度研发热带气旋多致灾因子复合链生关系的承灾体损失和风险量化模型,从而实现热带气旋多致灾因子损失和风险的精准和量化评估,为应急管理和风险防范提供重要支撑。

基于链式贝叶斯网络的跨海悬索桥高墩高塔多灾害风险评估

随着科技的进步和运输需求的增长,跨海悬索桥作为重要的交通枢纽,具有结构复杂、高柔度等主要特征,一旦发生损伤后果可能非常严重。高墩高塔作为其核心承重构件,长期暴露于复杂的海洋环境中,在全寿命周期内不可避免地面临多种自然灾害作用的威胁,工程风险不确定性极大。同时贝叶斯网络作为一种可以将变量的概率推理关系联系起来的图型模型,广泛应用于结构体系定量评估中。因此,针对跨海悬索桥研究现状及面临的环境问题,本研究提出一种基于贝叶斯网络的多灾害风险定量评估方法。首先分析灾害风险因子,针对结构和环境特点,选取地震、强风和洪水潮汐冲刷作为主要灾害作用,考虑结构体系中的关键构件或截面,根据弯矩曲率分析结果确定构件或截面的损伤级别范围;其次通过构件或截面与结构体系的从属关系及荷载场景模拟,建立贝叶斯网络模型,获得结构系统灾害风险概率;最终参考风险等级矩阵和桥梁运营可接受风险水平,对目标体系开展风险评估,并通过单一荷载下的对比结果对评估结果进行有效性验证。其中高墩高塔结构以在建伶仃洋大桥为例,风险评估结果为三级,在寿命运营期处于较安全状态,需制定必要的应急方案。研究结果表明,该方法可为同类型桥梁多灾害风险评估提供理论支持,对防灾减灾方案制订具有指导意义。

暴雨山洪与山坪塘漫坝多灾害耦合风险分析

为研究强降雨下山洪与漫坝耦合灾害对下游居民的影响程度和范围,应用HEC-RAS软件构建暴雨山洪与山坪塘漫坝多灾害耦合模型。首先,以重庆市巴南区某山坪塘为研究对象,根据巴南区暴雨强度公式设计不同重现期的降雨雨型;其次,借助数字高程数据对山坪塘进行原始构建,采用参数化模型对溃坝楔口参数进行预测,结合物理溃坝机制模拟漫坝过程;最后,选取洪水深度、洪水流速和洪水滞留时间等3个评价指标进行洪水风险分析。研究结果表明,突发强降雨下的山洪形成迅速且山坪塘发生漫坝的机率极大;山坪塘漫坝会加重附近区域的洪水风险等级。

水电工程施工安全隐患多标签文本智能分类方法

水利水电工程施工安全隐患体量大、形式多元、类型多样,同一隐患可能涉及多个类型,且隐患类型的界定存在模糊不清的现象。隐患分类多以人工经验为主导,极易导致隐患管理混淆,增加了隐患管理的难度。针对上述问题,本文提出了一种水电工程施工安全隐患文本多标签智能分类方法。首先,利用ALBERT模型对文本信息进行编码,实现非结构化安全隐患文本的高精度量化;然后,以文本量化结果为基础,考虑安全隐患中文本内容权重,利用Attention机制改进的双向门控循环单元(Bi-GRU),构建安全隐患文本多标签智能分类模型,提升施工安全隐患识别效率;最后,利用水电工程施工安全隐患文本,测试方法性能,得到方法的F1值达到了92.11%,证明了该方法的适用性,有望为水电工程施工的安全管理、事故隐患排查和分析提供信息支撑。

基于多源数据山区地质灾害监测预警应用

本文结合北斗卫星导航系统(BDS)/全球卫星导航系统(GNSS)技术和物联网传感器技术,建立了地质灾害监测平台系统,利用监测数据对常见的泥石流、崩塌以及不稳定斜坡地质灾害进行了数据分析。研究结果表明,长时序监测下BDS/GNSS监测精度达到毫米级。实时监测精度达到2cm。结合多源数据分析建立地质灾害防治多维度指标的预警系统,并重点对缓变形地质灾害数据进行了分析,为地质灾害防治工作提供重要的参考。

滑坡灾害InSAR早期识别关键技术方法研究

本研究重点关注了合成孔径雷达干涉测量(InSAR)技术在滑坡识别方面的应用,并着重分析了InSAR技术进行滑坡识别时所遇到的典型技术难题。首先,论文分析了InSAR多视处理作为预处理关键步骤的重要性,探讨了多视因子选择在噪声抑制和空间分辨率之间的平衡问题,并获得了最佳的多视因子参数。其次,本文讨论了干涉图滤波窗口对形变提取精度的影响,发现最佳的滤波窗口可有效保留形变信息,并抑制InSAR干涉噪声,有利于滑坡隐患的准确识别。此外,本研究还发现采用InSAR干涉图层面的大气校正处理,可避免InSAR相位解缠误差的传播,并有效削弱大气噪声,提高InSAR形变提取精度。最后,本研究讨论了InSAR干涉对筛选中的长短时间基线问题,发现仅利用短时间基线干涉对较难捕捉滑坡小量级形变,而长时间基线又不可避免面临干涉失相关的挑战,因此,以短时间基线干涉对为基础,辅以一定数量的高质量长时间基线干涉对,是更为可靠的小量级运动滑坡隐患InSAR识别干涉对筛选策略。最后,研究以金沙江上游某滑坡密集区域为例,基于最优参数和对照参数组开展了实验,验证了最优参数组的有效性和适用性。上述研究成果显著深化了InSAR技术在地质灾害识别应用中的适用性和局限性,为利用InSAR技术开展滑坡灾害早期识别提供了科学的支撑,具有重要的理论和实用价值。