Debris flow hazards seriously threaten thesafety and sustainable development of mountainousareas. Numerous debris flow mitigation measures havebeen implemented worldwide;however, acomprehensive assessment of the speci...Debris flow hazards seriously threaten thesafety and sustainable development of mountainousareas. Numerous debris flow mitigation measures havebeen implemented worldwide;however, acomprehensive assessment of the specific disasterreduction effects of these measures and their economic,social and ecological benefits is yet to be performed.The western region of Sichuan Province frequentlysuffers from geohazards such as debris flow, and thegovernment has adopted many mitigation measures.This study assessed the benefits of debris flowmitigation measures and identified the key influencingfactors via a field-based study conducted in 81 villagesin western Sichuan province, China. A framework forthe evaluation of the benefits of rural debris flowmitigation measures was constructed andquantitatively evaluated using a survey. Snowballsampling was performed to recruit 81 village leadersand 468 farmers. The results showed that managementand engineering measures were the main methodsused to mitigate debris flow;ecological measures wereauxiliary. The average satisfaction scores of farmers forthese three types of measures were 4.07, 3.90, and 3.56,respectively (as measured on a five-point Likert scale).In contrast, in terms of the benefits of these mitigationmeasures, only a small proportion of villages (11.11%)obtained a high level of comprehensive benefits fromthe debris flow mitigation measures, while the majority(88.89%) received medium to low-level benefits. Toimprove this situation, we further studied and foundthat the main factors that restricted villages fromachieving high-level comprehensive benefits were theunpredictable nature of debris flows, labour forceoutflow and remoteness. Effective control measures, agood economic environment and strong governmentassistance were reported as crucial factors forimproving these comprehensive benefits. This studyprovides socio-scientific references for decisionmakingon rural debris flow mitigation measures while keeping villages at the centre of economic development.展开更多
Wheel polygonal wear can immensely worsen wheel/rail interactions and vibration performances of the train and track,and ultimately,lead to the shortening of service life of railway components.At present,wheel/rail med...Wheel polygonal wear can immensely worsen wheel/rail interactions and vibration performances of the train and track,and ultimately,lead to the shortening of service life of railway components.At present,wheel/rail medium-or high-frequency frictional interactions are perceived as an essential reason of the high-order polygonal wear of railway wheels,which are potentially resulted by the flexible deformations of the train/track system or other external excitations.In this work,the effect of wheel/rail flexibility on polygonal wear evolution of heavy-haul locomotive wheels is explored with aid of the long-term wheel polygonal wear evolution simulations,in which different flexible modeling of the heavy-haul wheel/rail coupled system is implemented.Further,the mitigation measures for the polygonal wear of heavy-haul locomotive wheels are discussed.The results point out that the evolution of polygonal wear of heavy-haul locomotive wheels can be veritably simulated with consideration of the flexible effect of both wheelset and rails.Execution of mixed-line operation of heavy-haul trains and application of multicut wheel re-profiling can effectively reduce the development of wheel polygonal wear.This research can provide a deep-going understanding of polygonal wear evolution mechanism of heavy-haul locomotive wheels and its mitigation measures.展开更多
Long-runout rockslides at high altitude could cause disaster chain in river basins and destroy towns and major infrasturctures.This paper firstly explores the initiation mechanism of high-altitude and long-runout rock...Long-runout rockslides at high altitude could cause disaster chain in river basins and destroy towns and major infrasturctures.This paper firstly explores the initiation mechanism of high-altitude and long-runout rockslides.Two types of sliding-prone geostructure models,i.e.the fault control type in orogenic belt and the fold control type in platform area,are proposed.Then,large-scale experimental apparatus and associated numerical simulations are conducted to understanding the chain-style dynamics of rockslide-debris avalanche-debris flow.The results reveal the fragmentation effects,the rheological behaviors and the boundary layer effect of long-runout avalanche-debris flow.The dynamic character-istics of quasi-static-transition-inertia state and solid-liquid coupling in rapid movement of rockslide-debris avalanche-debris flow are investigated.Finally,the risk mitigation strategy of the non-structure and structure for resilient energy dissipation are illustrated for initiation,transition and deposition zones.The structural prevention and mitigation methods have been successfully applied to the high-altitude and long-runout rockslides in Zhouqu and Maoxian of the Wenchuan earthquake zone,as well as the other major geohazards in Qinghai-Tibet Plateau and its adjacent areas.展开更多
The design of remediation works for the mitigation and prevention of the associated risk is needed where these geological hazards affect anthropized areas. Remedial measures for landslides commonly include slope resha...The design of remediation works for the mitigation and prevention of the associated risk is needed where these geological hazards affect anthropized areas. Remedial measures for landslides commonly include slope reshaping, plumbing, drainage, retaining structures and internal slope reinforcement, while debris flow control works consist in open or closed control structures. The effectiveness of the remedial works implemented must be assessed by evaluating the reduction of the risk over time. The choice of the most appropriate and cost-effective intervention must consider the type of hazard and environmental issues, and selects, wherever possible, naturalistic engineering operations that are consequently implemented according to the environmental regulations or the design and specification standards imposed by the competent public administrations. The mitigation procedures consist of five basic steps:(a) acquisition of the knowledge of the hazard process;(b) risk assessment with identification of possible disaster scenarios;(c) planning and designing of specific remedial measures to reduce and/or eliminate the potential risk;(d) slope monitoring after application of remedial measures,(e) transfer of knowledge to the stakeholders. This paper presents two case studies describing the practice for the design of the mitigation measures adopted for debris flow and active landslide sites in North-Eastern Italy. The first case study is a debris flow site, for which, based on observation of past events and numerical simulations using the software FLOW-2D, the most suitable mitigation measures were found to be the construction of a debris basin, barriers and breakers. The second case study deals with an active landslide threatening a village. Based on the landslide kinematics and the results of numerical simulations performed with the code FLAC, hard engineering remedial works were planned to reduce the driving forces with benching and by increasing the available resisting forces using jet grout piles and deep drainage.展开更多
Impact pile driving is an interesting technique for the construction of deep foundations from a practical and economical point of view.However,the generalization of this technique can be restricted due to the excessiv...Impact pile driving is an interesting technique for the construction of deep foundations from a practical and economical point of view.However,the generalization of this technique can be restricted due to the excessive vibration levels that can be generated,which can be especially problematic in residential areas.However,different mitigation measures can be applied to prevent excessive vibration levels inside buildings located near construction sites.To compare its efficiency through a numerical prediction tool,two experimental test sites are first presented and characterized.From the results obtained,it was found that the construction of an open trench near the impact source can be used as an efficient mitigation measure to reduce the maximum vibration levels evaluated in this study.展开更多
Deep foundation pit excavation is a basic and key step involved in modern building construction.In order to ensure the construction quality and safety of deep foundation pits,this paper takes a project as an example t...Deep foundation pit excavation is a basic and key step involved in modern building construction.In order to ensure the construction quality and safety of deep foundation pits,this paper takes a project as an example to analyze deep foundation pit excavation technology,including the nature of this construction project,the main technical measures in the construction of deep foundation pit,and the analysis of the safety risk prevention and control measures.The purpose of this analysis is to provide scientific reference for the construction quality and safety of deep foundation pits.展开更多
In this paper, we focus on anticipated backward stochastic Volterra integral equations(ABSVIEs) with jumps. We solve the problem of the well-posedness of so-called M-solutions to this class of equation, and analytical...In this paper, we focus on anticipated backward stochastic Volterra integral equations(ABSVIEs) with jumps. We solve the problem of the well-posedness of so-called M-solutions to this class of equation, and analytically derive a comparison theorem for them and for the continuous equilibrium consumption process. These continuous equilibrium consumption processes can be described by the solutions to this class of ABSVIE with jumps.Motivated by this, a class of dynamic risk measures induced by ABSVIEs with jumps are discussed.展开更多
Bridges serve as essential parts of transportation infrastructure,facilitating the movement of people and goods across rivers,valleys,and other obstacles.However,they are also susceptible to a wide range of natural ha...Bridges serve as essential parts of transportation infrastructure,facilitating the movement of people and goods across rivers,valleys,and other obstacles.However,they are also susceptible to a wide range of natural hazards,including floods,earthquakes,and landslides,which can damage or even collapse these structures,leading to severe economic and human losses.A risk index has been developed to address this issue,which quantifies the likelihood and severity of natural hazards occurring in a specific location.The application of risk indices for natural hazards in bridge management involves a data collection process and mathematical modelling.The data collection process gathers information on bridges’location,condition,and vulnerability,while mathematical modelling uses the data to assess the risk of natural hazards.Overall,risk indices provide a quantitative measure of the vulnerability of bridges to natural hazards and help to prioritize maintenance and repair activities.Mitigation measures are then evaluated and implemented based on the risk assessment results.By using this tool,the UBMS research group has developed an algorithm for risk assessment which will be essential in the decision-making process,specifically focused on enhancing Fund Optimization,Deterioration Modelling,and Risk Analysis.These developments effectively fulfill the primary objectives associated with addressing and mitigating hazards.This development also helps bridge managers understand the potential threats posed by natural hazards and allocate resources more efficiently to ensure the safety and longevity of critical transportation infrastructure.展开更多
Hydrogen challenge mitigation stands as one of the main objectives in the management of severe accidents at Nuclear Power Plants (NPPs). Key strategies for hydrogen control include atmospheric inertization and hydroge...Hydrogen challenge mitigation stands as one of the main objectives in the management of severe accidents at Nuclear Power Plants (NPPs). Key strategies for hydrogen control include atmospheric inertization and hydrogen removal with Passive Autocatalytic Recombiners (PARs) being a commonly accepted approach. However, an examination of PAR operation specificity reveals potential inefficiencies and reliability issues in certain severe accident scenarios. Moreover, during the in-vessel stage of severe accident development, in some severe accident scenarios PARs can unexpectedly become a source of hydrogen detonation. The effectiveness of hydrogen removal systems depends on various factors, including the chosen strategies, severe accident scenarios, reactor building design, and other influencing factors. Consequently, a comprehensive hydrogen mitigation strategy must effectively incorporate a combination of strategies rather than be based on one strategy, taking into consideration the probabilistic risks and uncertainties associated with the implementation of PARs or other traditional methods. In response to these considerations, within the framework of this research it has been suggested a conceptual strategy to mitigate the hydrogen challenge during the in-vessel stage of severe accident development.展开更多
This review focuses on major contemporary empirical studies that examine both the physical and regulatory sides of climate risk. These studies explore how climate risk affects firms’ operating performance and leverag...This review focuses on major contemporary empirical studies that examine both the physical and regulatory sides of climate risk. These studies explore how climate risk affects firms’ operating performance and leverage, stock and bond valuation, cost of capital, and managerial behavior. We also discuss how the effect of climate risk on real estate markets depends on individuals’ beliefs about climate change. Furthermore, we summarize papers on climate risk activism and how firms can employ financial devices and technology to mitigate their climate risk. Finally, we make some recommendations for further research areas.展开更多
Using summer(June-August)precipitation observation data in 10 representative stations of Shaoyang City during 1971-2021 and disaster data caused by summer rainstorm in nine counties(cities)and four districts of Shaoya...Using summer(June-August)precipitation observation data in 10 representative stations of Shaoyang City during 1971-2021 and disaster data caused by summer rainstorm in nine counties(cities)and four districts of Shaoyang during 1981-2021,statistical analysis on summer rainstorm and its caused disaster in Shaoyang was conducted,and spatial and temporal characteristics of summer rainstorm and spatial distribution rule of disaster were found out.The results showed that(1)the rainstorm disaster in Shaoyang City occurs almost every year and is highly seasonal.(2)Rainstorm disaster loss is the first of other meteorological disasters.(3)The summer rainstorm disaster has the characteristics of sudden and destructive.On this basis,the relative grades of rainstorm disaster risk degree and disaster loss degree were divided,and the risk assessment of rainstorm and flood disaster in Shaoyang City was made,and the disaster prevention and mitigation measures and countermeasures were put forward.The research could provide scientific decision basis for party and government departments guiding flood fighting and disaster relief.展开更多
Dongtan is set to be developed as a sustainable urban-rural integration,aiming to attract a wide range of commercial and leisure investments.The Shanghai Industrial Investment Corporation(SIIC),the largest internation...Dongtan is set to be developed as a sustainable urban-rural integration,aiming to attract a wide range of commercial and leisure investments.The Shanghai Industrial Investment Corporation(SIIC),the largest international investment group owned by the Shanghai municipal government,is leading the Dongtan project in partnership with Arup.The project’s risks are categorized into eight major groups:(1)Force majeure,(2)people-related risks,(3)financial and economic risks,(4)political and country risks,(5)environmental risks,(6)completion-related risks,(7)design-related risks,and(8)technology risks.Among these,political risk is particularly notable for its high probability and significant impact.Effective project risk management is essential to foresee and address uncertainties that could jeopardize the project’s objectives and timelines.Appropriate strategies must be implemented to manage and mitigate these risks.展开更多
Constructing a metro station by enlarging shield tunnels combined with a mining/cut-and-cover method provides a new method to solve the contradictions of construction time limits of shield tunnels and stations. As a n...Constructing a metro station by enlarging shield tunnels combined with a mining/cut-and-cover method provides a new method to solve the contradictions of construction time limits of shield tunnels and stations. As a new-style construction method, there are several specific risks involved in the construction process. Based on the test section of Sanyuanqiao station on Beijing metro line 10, and combined with the existing methods of risk identification at present, including a review of world-wide operational experience of similar projects, the study of generic guidance on hazards associated with the type of work being undertaken, and discussions with qualified and experienced staff from the project team, etc., the specific risks during the construction process of the metro station constructed by enlarging shield tunnels combined with the cut-and-cover method are identified. The results show that the specific risks mainly come from three construction processes which include constructing upper enclosure structures, excavating the soil between shield tunnels and demolishing shield segments. Then relevant risk mitigation measures are put forward. The results can provide references for scheme improvement and a comprehensive risk assessment of the new-style construction method.展开更多
In this paper, from the viewpoint of the time value of money, we study the risk measures for portfolio vectors with discount factor. Cash subadditive risk measures for portfolio vectors are proposed. Representation re...In this paper, from the viewpoint of the time value of money, we study the risk measures for portfolio vectors with discount factor. Cash subadditive risk measures for portfolio vectors are proposed. Representation results are given by two different methods which are convex analysis and enlarging space. Especially, the method of convex analysis make the line of reasoning and the representation result be simpler. Meanwhile, spot and forward risk measures for portfolio vectors are also introduced, and the relationships between them are investigated.展开更多
In this paper, by an axiomatic approach, we propose the concepts of comonotonic subadditivity and comonotonic convex risk measures for portfolios, which are extensions of the ones introduced by Song and Yan (2006). ...In this paper, by an axiomatic approach, we propose the concepts of comonotonic subadditivity and comonotonic convex risk measures for portfolios, which are extensions of the ones introduced by Song and Yan (2006). Representation results for these new introduced risk measures for portfolios are given in terms of Choquet integrals. Links of these newly introduced risk measures to multi-period comonotonic risk measures are represented. Finally, applications of the newly introduced comonotonic coherent risk measures to capital allocations are provided.展开更多
In this paper, new risk measures are introduced, tation results are also given. These newly introduced risk introduced by Song and Yan (2009) and Karoui (2009). and the corresponding represen- measures are extens...In this paper, new risk measures are introduced, tation results are also given. These newly introduced risk introduced by Song and Yan (2009) and Karoui (2009). and the corresponding represen- measures are extensions of those展开更多
Pesticide is one of the major inputs in modern agriculture and its uses are increasing annually. Pesticides are seen as inherently benign, in the same way that medicines are. Many local languages even use the same wor...Pesticide is one of the major inputs in modern agriculture and its uses are increasing annually. Pesticides are seen as inherently benign, in the same way that medicines are. Many local languages even use the same word for “pesticide” and “medicine</span><span style="font-family:Verdana;">”</span><span style="font-family:""><span style="font-family:Verdana;">. Along with the increasing consumption of pesticides, Highly Hazardous Pesticides (HHPs), which are more toxic are still in widespread use in Asia and constitute a substantial challenge to human health and </span><span style="font-family:Verdana;">the environment especially in low- and middle-income countries with less</span><span style="font-family:Verdana;"> resources, training and capacities to deal with them. Reducing the risks posed by HHPs has become a priority in various international chemicals manage</span><span style="font-family:Verdana;">ment policies, and many countries have started taking action accordingly</span><span style="font-family:Verdana;">. </span><span style="font-family:Verdana;">The objective of the paper is to establish the national status of the use of </span><span style="font-family:Verdana;">HHPs in Asia in line with FAO/WHO criteria for HHPs and encourage deli</span><span style="font-family:Verdana;">berate consideration of mitigation options for effective management of</span><span style="font-family:Verdana;"> HHPs. This report is based on the nationally registered pesticide active ingredients and other related information obtained from Pesticide Registration Authorities of 13 Asian countries and research reports of different national and international journals. There are currently about 3557 pesticide products (active ingredients) registered in 13 Asian countries to control pests on crops and for public health uses, and 214 HHPs among the list of registered pesticides still in use in these Asian countries. An analysis of the list of registered formulated products revealed that 61 different active ingredients are included in these 214 registered HHPs in Asian countries. Considering the global concern of </span><span style="font-family:Verdana;">HHPs, there is thus every reason to develop mass awareness raising pro</span><span style="font-family:Verdana;">grammes based on knowledge, aptitude and practices and to disseminate</span><span style="font-family:Verdana;"> them within the community in order to inform about the risks of HHPs and to replace HHPs and mitigate human risk and exposure to HHPs. It is concluded that detailed surveys and studies should be formulated with help of experts from academia and research organizations to construct a baseline data which may be helpful to tone down the HHP situation in the country</span></span><span style="font-family:Verdana;">.展开更多
In the development of the Severe Accident Management Guidelines (SAMG), it is very important to choose the main severe accident sequences and verify their mitigation measures. In this article, Loss-of-Coolant Ac- cide...In the development of the Severe Accident Management Guidelines (SAMG), it is very important to choose the main severe accident sequences and verify their mitigation measures. In this article, Loss-of-Coolant Ac- cident (LOCA), Steam Generator Tube Rupture (SGTR), Station Blackout (SBO), and Anticipated Transients without Scram (ATWS) in PWR with 300 MWe are selected as the main severe accident sequences. The core damage pro- gressions induced by the above-mentioned sequences are analyzed using SCDAP/RELAP5. To arrest the core damage progression and mitigate the consequences of severe accidents, the measures for the severe accident management (SAM) such as feed and bleed, and depressurizations are verified using the calculation. The results suggest that im- plementing feed and bleed and depressurization could be an effective way to arrest the severe accident sequences in PWR.展开更多
Based on the analysis of construction project safety risk and its preventive measures, it is first necessary to clarify the safety risks and existing problems of construction project supervision and to formulate effec...Based on the analysis of construction project safety risk and its preventive measures, it is first necessary to clarify the safety risks and existing problems of construction project supervision and to formulate effective construction procedures. It is necessary to check the production safety of the construction unit, strengthen the company's own safety production management, and reasonably control the risk to familiarize with the construction drawings, and make a special construction plan for the work of the bottom line. Finally, an elective solution is drawn to comprehensively expound the importance of construction project construction safety risk and its preventive measures.展开更多
Numerous Quaternary deposits are existed in the mountainous areas of Southwest China,especially in the transition zone between the QinghaiTibet Plateau and the Sichuan Basin,where strong tectonic movements and frequen...Numerous Quaternary deposits are existed in the mountainous areas of Southwest China,especially in the transition zone between the QinghaiTibet Plateau and the Sichuan Basin,where strong tectonic movements and frequent climatic changes increase the potential landslides.The possible deformation and failure process of potential landslides and their impacts on the surrounding environment are important research topics.Field investigation and monitoring indicate that the Qingliu landslide in Xiameng town,Li County,Sichuan Province,China has been continuously deforming since August 2020.The deformation zone has a maximum deformation depth of approximately 18.9m,a total area of 54,628 m2,and a volume of 34.0×104 m3,which seriously threatens infrastructure projects and dwellings.As a result,understanding the Qingliu landslide evolution process,assessing the hazard risk,and planning disaster prevention measures are of great significance for reducing disaster loss.In this study,the mass movement process and hazard risk of the Qingliu landslide are evaluated,and the effects of different prevention measures are compared and discussed.By using the depth-integrated method,the mass movement of the Qingliu landslide is analyzed.The numerical simulation results indicate that the maximum velocity of the Qingliu landslide is approximately 37.5 m/s,and the duration of the landslide is approximately 90s.The simulated landslide can eventually form a deposited mass with a maximum deposit thickness of 19.4 m and an area of approximately 60,168.3 m2,thereby blocking the river and burying dwellings.Furthermore,a risk assessment of the Qingliu landslide under different forms of protection measures is also produced and discussed by considering the hazard level and economic vulnerability level of the affected area.Setting three layers of anti-slide piles on the deformation zone to reduce the hazard risk of the Qingliu landslide is a better choice.Our results may be useful for planning prevention measures and improving disaster emergency response systems.展开更多
基金supported by the Science and Technology Research Program of the Institute of Mountain Hazards and Environment,Chinese Academy of Sciences(Grant No.IMHE-ZDRW-08)the Sichuan Science and Technology Program(Grant No.2022JDR0209).
文摘Debris flow hazards seriously threaten thesafety and sustainable development of mountainousareas. Numerous debris flow mitigation measures havebeen implemented worldwide;however, acomprehensive assessment of the specific disasterreduction effects of these measures and their economic,social and ecological benefits is yet to be performed.The western region of Sichuan Province frequentlysuffers from geohazards such as debris flow, and thegovernment has adopted many mitigation measures.This study assessed the benefits of debris flowmitigation measures and identified the key influencingfactors via a field-based study conducted in 81 villagesin western Sichuan province, China. A framework forthe evaluation of the benefits of rural debris flowmitigation measures was constructed andquantitatively evaluated using a survey. Snowballsampling was performed to recruit 81 village leadersand 468 farmers. The results showed that managementand engineering measures were the main methodsused to mitigate debris flow;ecological measures wereauxiliary. The average satisfaction scores of farmers forthese three types of measures were 4.07, 3.90, and 3.56,respectively (as measured on a five-point Likert scale).In contrast, in terms of the benefits of these mitigationmeasures, only a small proportion of villages (11.11%)obtained a high level of comprehensive benefits fromthe debris flow mitigation measures, while the majority(88.89%) received medium to low-level benefits. Toimprove this situation, we further studied and foundthat the main factors that restricted villages fromachieving high-level comprehensive benefits were theunpredictable nature of debris flows, labour forceoutflow and remoteness. Effective control measures, agood economic environment and strong governmentassistance were reported as crucial factors forimproving these comprehensive benefits. This studyprovides socio-scientific references for decisionmakingon rural debris flow mitigation measures while keeping villages at the centre of economic development.
基金Supported by National Natural Science Foundation of China(Grant Nos.U2268210,52302474,52072249).
文摘Wheel polygonal wear can immensely worsen wheel/rail interactions and vibration performances of the train and track,and ultimately,lead to the shortening of service life of railway components.At present,wheel/rail medium-or high-frequency frictional interactions are perceived as an essential reason of the high-order polygonal wear of railway wheels,which are potentially resulted by the flexible deformations of the train/track system or other external excitations.In this work,the effect of wheel/rail flexibility on polygonal wear evolution of heavy-haul locomotive wheels is explored with aid of the long-term wheel polygonal wear evolution simulations,in which different flexible modeling of the heavy-haul wheel/rail coupled system is implemented.Further,the mitigation measures for the polygonal wear of heavy-haul locomotive wheels are discussed.The results point out that the evolution of polygonal wear of heavy-haul locomotive wheels can be veritably simulated with consideration of the flexible effect of both wheelset and rails.Execution of mixed-line operation of heavy-haul trains and application of multicut wheel re-profiling can effectively reduce the development of wheel polygonal wear.This research can provide a deep-going understanding of polygonal wear evolution mechanism of heavy-haul locomotive wheels and its mitigation measures.
基金This work was financially supported by National Natural Science Foundation of China(Grant Nos.U2244226,U2244227 and 42177172).
文摘Long-runout rockslides at high altitude could cause disaster chain in river basins and destroy towns and major infrasturctures.This paper firstly explores the initiation mechanism of high-altitude and long-runout rockslides.Two types of sliding-prone geostructure models,i.e.the fault control type in orogenic belt and the fold control type in platform area,are proposed.Then,large-scale experimental apparatus and associated numerical simulations are conducted to understanding the chain-style dynamics of rockslide-debris avalanche-debris flow.The results reveal the fragmentation effects,the rheological behaviors and the boundary layer effect of long-runout avalanche-debris flow.The dynamic character-istics of quasi-static-transition-inertia state and solid-liquid coupling in rapid movement of rockslide-debris avalanche-debris flow are investigated.Finally,the risk mitigation strategy of the non-structure and structure for resilient energy dissipation are illustrated for initiation,transition and deposition zones.The structural prevention and mitigation methods have been successfully applied to the high-altitude and long-runout rockslides in Zhouqu and Maoxian of the Wenchuan earthquake zone,as well as the other major geohazards in Qinghai-Tibet Plateau and its adjacent areas.
文摘The design of remediation works for the mitigation and prevention of the associated risk is needed where these geological hazards affect anthropized areas. Remedial measures for landslides commonly include slope reshaping, plumbing, drainage, retaining structures and internal slope reinforcement, while debris flow control works consist in open or closed control structures. The effectiveness of the remedial works implemented must be assessed by evaluating the reduction of the risk over time. The choice of the most appropriate and cost-effective intervention must consider the type of hazard and environmental issues, and selects, wherever possible, naturalistic engineering operations that are consequently implemented according to the environmental regulations or the design and specification standards imposed by the competent public administrations. The mitigation procedures consist of five basic steps:(a) acquisition of the knowledge of the hazard process;(b) risk assessment with identification of possible disaster scenarios;(c) planning and designing of specific remedial measures to reduce and/or eliminate the potential risk;(d) slope monitoring after application of remedial measures,(e) transfer of knowledge to the stakeholders. This paper presents two case studies describing the practice for the design of the mitigation measures adopted for debris flow and active landslide sites in North-Eastern Italy. The first case study is a debris flow site, for which, based on observation of past events and numerical simulations using the software FLOW-2D, the most suitable mitigation measures were found to be the construction of a debris basin, barriers and breakers. The second case study deals with an active landslide threatening a village. Based on the landslide kinematics and the results of numerical simulations performed with the code FLAC, hard engineering remedial works were planned to reduce the driving forces with benching and by increasing the available resisting forces using jet grout piles and deep drainage.
基金Programmatic funding-UIDP/04708/2020 of the CONSTRUCT-Instituto de I&D em Estruturas e Construções-funded by national funds through the FCT/MCTES(PIDDAC)Project PTDC/ECI-CON/29634/2017-POCI-01-0145-FEDER-029634-funded by FEDER funds through COMPETE2020-Programa Operacional Competitividade e Internacionalização(POCI)by national funds(PIDDAC)through FCT/MCTES。
文摘Impact pile driving is an interesting technique for the construction of deep foundations from a practical and economical point of view.However,the generalization of this technique can be restricted due to the excessive vibration levels that can be generated,which can be especially problematic in residential areas.However,different mitigation measures can be applied to prevent excessive vibration levels inside buildings located near construction sites.To compare its efficiency through a numerical prediction tool,two experimental test sites are first presented and characterized.From the results obtained,it was found that the construction of an open trench near the impact source can be used as an efficient mitigation measure to reduce the maximum vibration levels evaluated in this study.
文摘Deep foundation pit excavation is a basic and key step involved in modern building construction.In order to ensure the construction quality and safety of deep foundation pits,this paper takes a project as an example to analyze deep foundation pit excavation technology,including the nature of this construction project,the main technical measures in the construction of deep foundation pit,and the analysis of the safety risk prevention and control measures.The purpose of this analysis is to provide scientific reference for the construction quality and safety of deep foundation pits.
基金supported by the National Natural Science Foundation of China (11901184, 11771343)the Natural Science Foundation of Hunan Province (2020JJ5025)。
文摘In this paper, we focus on anticipated backward stochastic Volterra integral equations(ABSVIEs) with jumps. We solve the problem of the well-posedness of so-called M-solutions to this class of equation, and analytically derive a comparison theorem for them and for the continuous equilibrium consumption process. These continuous equilibrium consumption processes can be described by the solutions to this class of ABSVIE with jumps.Motivated by this, a class of dynamic risk measures induced by ABSVIEs with jumps are discussed.
文摘Bridges serve as essential parts of transportation infrastructure,facilitating the movement of people and goods across rivers,valleys,and other obstacles.However,they are also susceptible to a wide range of natural hazards,including floods,earthquakes,and landslides,which can damage or even collapse these structures,leading to severe economic and human losses.A risk index has been developed to address this issue,which quantifies the likelihood and severity of natural hazards occurring in a specific location.The application of risk indices for natural hazards in bridge management involves a data collection process and mathematical modelling.The data collection process gathers information on bridges’location,condition,and vulnerability,while mathematical modelling uses the data to assess the risk of natural hazards.Overall,risk indices provide a quantitative measure of the vulnerability of bridges to natural hazards and help to prioritize maintenance and repair activities.Mitigation measures are then evaluated and implemented based on the risk assessment results.By using this tool,the UBMS research group has developed an algorithm for risk assessment which will be essential in the decision-making process,specifically focused on enhancing Fund Optimization,Deterioration Modelling,and Risk Analysis.These developments effectively fulfill the primary objectives associated with addressing and mitigating hazards.This development also helps bridge managers understand the potential threats posed by natural hazards and allocate resources more efficiently to ensure the safety and longevity of critical transportation infrastructure.
文摘Hydrogen challenge mitigation stands as one of the main objectives in the management of severe accidents at Nuclear Power Plants (NPPs). Key strategies for hydrogen control include atmospheric inertization and hydrogen removal with Passive Autocatalytic Recombiners (PARs) being a commonly accepted approach. However, an examination of PAR operation specificity reveals potential inefficiencies and reliability issues in certain severe accident scenarios. Moreover, during the in-vessel stage of severe accident development, in some severe accident scenarios PARs can unexpectedly become a source of hydrogen detonation. The effectiveness of hydrogen removal systems depends on various factors, including the chosen strategies, severe accident scenarios, reactor building design, and other influencing factors. Consequently, a comprehensive hydrogen mitigation strategy must effectively incorporate a combination of strategies rather than be based on one strategy, taking into consideration the probabilistic risks and uncertainties associated with the implementation of PARs or other traditional methods. In response to these considerations, within the framework of this research it has been suggested a conceptual strategy to mitigate the hydrogen challenge during the in-vessel stage of severe accident development.
文摘This review focuses on major contemporary empirical studies that examine both the physical and regulatory sides of climate risk. These studies explore how climate risk affects firms’ operating performance and leverage, stock and bond valuation, cost of capital, and managerial behavior. We also discuss how the effect of climate risk on real estate markets depends on individuals’ beliefs about climate change. Furthermore, we summarize papers on climate risk activism and how firms can employ financial devices and technology to mitigate their climate risk. Finally, we make some recommendations for further research areas.
文摘Using summer(June-August)precipitation observation data in 10 representative stations of Shaoyang City during 1971-2021 and disaster data caused by summer rainstorm in nine counties(cities)and four districts of Shaoyang during 1981-2021,statistical analysis on summer rainstorm and its caused disaster in Shaoyang was conducted,and spatial and temporal characteristics of summer rainstorm and spatial distribution rule of disaster were found out.The results showed that(1)the rainstorm disaster in Shaoyang City occurs almost every year and is highly seasonal.(2)Rainstorm disaster loss is the first of other meteorological disasters.(3)The summer rainstorm disaster has the characteristics of sudden and destructive.On this basis,the relative grades of rainstorm disaster risk degree and disaster loss degree were divided,and the risk assessment of rainstorm and flood disaster in Shaoyang City was made,and the disaster prevention and mitigation measures and countermeasures were put forward.The research could provide scientific decision basis for party and government departments guiding flood fighting and disaster relief.
文摘Dongtan is set to be developed as a sustainable urban-rural integration,aiming to attract a wide range of commercial and leisure investments.The Shanghai Industrial Investment Corporation(SIIC),the largest international investment group owned by the Shanghai municipal government,is leading the Dongtan project in partnership with Arup.The project’s risks are categorized into eight major groups:(1)Force majeure,(2)people-related risks,(3)financial and economic risks,(4)political and country risks,(5)environmental risks,(6)completion-related risks,(7)design-related risks,and(8)technology risks.Among these,political risk is particularly notable for its high probability and significant impact.Effective project risk management is essential to foresee and address uncertainties that could jeopardize the project’s objectives and timelines.Appropriate strategies must be implemented to manage and mitigate these risks.
基金Beijing Science and Technology Planning Project(No.D0604003040921)
文摘Constructing a metro station by enlarging shield tunnels combined with a mining/cut-and-cover method provides a new method to solve the contradictions of construction time limits of shield tunnels and stations. As a new-style construction method, there are several specific risks involved in the construction process. Based on the test section of Sanyuanqiao station on Beijing metro line 10, and combined with the existing methods of risk identification at present, including a review of world-wide operational experience of similar projects, the study of generic guidance on hazards associated with the type of work being undertaken, and discussions with qualified and experienced staff from the project team, etc., the specific risks during the construction process of the metro station constructed by enlarging shield tunnels combined with the cut-and-cover method are identified. The results show that the specific risks mainly come from three construction processes which include constructing upper enclosure structures, excavating the soil between shield tunnels and demolishing shield segments. Then relevant risk mitigation measures are put forward. The results can provide references for scheme improvement and a comprehensive risk assessment of the new-style construction method.
基金Supported by the National Natural Science Foundation of China(11371284,11771343)
文摘In this paper, from the viewpoint of the time value of money, we study the risk measures for portfolio vectors with discount factor. Cash subadditive risk measures for portfolio vectors are proposed. Representation results are given by two different methods which are convex analysis and enlarging space. Especially, the method of convex analysis make the line of reasoning and the representation result be simpler. Meanwhile, spot and forward risk measures for portfolio vectors are also introduced, and the relationships between them are investigated.
基金Supported by the National Natural Science Foundation of China(11371284)the Natural Science Foundation of Henan Province(14B110037)
文摘In this paper, by an axiomatic approach, we propose the concepts of comonotonic subadditivity and comonotonic convex risk measures for portfolios, which are extensions of the ones introduced by Song and Yan (2006). Representation results for these new introduced risk measures for portfolios are given in terms of Choquet integrals. Links of these newly introduced risk measures to multi-period comonotonic risk measures are represented. Finally, applications of the newly introduced comonotonic coherent risk measures to capital allocations are provided.
基金Supported in part by the National Natural Science Foundation of China (10971157)Key Projects of Philosophy and Social Sciences Research+1 种基金Ministry of Education of China (09JZD0027)The Talent Introduction Projects of Nanjing Audit University
文摘In this paper, new risk measures are introduced, tation results are also given. These newly introduced risk introduced by Song and Yan (2009) and Karoui (2009). and the corresponding represen- measures are extensions of those
文摘Pesticide is one of the major inputs in modern agriculture and its uses are increasing annually. Pesticides are seen as inherently benign, in the same way that medicines are. Many local languages even use the same word for “pesticide” and “medicine</span><span style="font-family:Verdana;">”</span><span style="font-family:""><span style="font-family:Verdana;">. Along with the increasing consumption of pesticides, Highly Hazardous Pesticides (HHPs), which are more toxic are still in widespread use in Asia and constitute a substantial challenge to human health and </span><span style="font-family:Verdana;">the environment especially in low- and middle-income countries with less</span><span style="font-family:Verdana;"> resources, training and capacities to deal with them. Reducing the risks posed by HHPs has become a priority in various international chemicals manage</span><span style="font-family:Verdana;">ment policies, and many countries have started taking action accordingly</span><span style="font-family:Verdana;">. </span><span style="font-family:Verdana;">The objective of the paper is to establish the national status of the use of </span><span style="font-family:Verdana;">HHPs in Asia in line with FAO/WHO criteria for HHPs and encourage deli</span><span style="font-family:Verdana;">berate consideration of mitigation options for effective management of</span><span style="font-family:Verdana;"> HHPs. This report is based on the nationally registered pesticide active ingredients and other related information obtained from Pesticide Registration Authorities of 13 Asian countries and research reports of different national and international journals. There are currently about 3557 pesticide products (active ingredients) registered in 13 Asian countries to control pests on crops and for public health uses, and 214 HHPs among the list of registered pesticides still in use in these Asian countries. An analysis of the list of registered formulated products revealed that 61 different active ingredients are included in these 214 registered HHPs in Asian countries. Considering the global concern of </span><span style="font-family:Verdana;">HHPs, there is thus every reason to develop mass awareness raising pro</span><span style="font-family:Verdana;">grammes based on knowledge, aptitude and practices and to disseminate</span><span style="font-family:Verdana;"> them within the community in order to inform about the risks of HHPs and to replace HHPs and mitigate human risk and exposure to HHPs. It is concluded that detailed surveys and studies should be formulated with help of experts from academia and research organizations to construct a baseline data which may be helpful to tone down the HHP situation in the country</span></span><span style="font-family:Verdana;">.
文摘In the development of the Severe Accident Management Guidelines (SAMG), it is very important to choose the main severe accident sequences and verify their mitigation measures. In this article, Loss-of-Coolant Ac- cident (LOCA), Steam Generator Tube Rupture (SGTR), Station Blackout (SBO), and Anticipated Transients without Scram (ATWS) in PWR with 300 MWe are selected as the main severe accident sequences. The core damage pro- gressions induced by the above-mentioned sequences are analyzed using SCDAP/RELAP5. To arrest the core damage progression and mitigate the consequences of severe accidents, the measures for the severe accident management (SAM) such as feed and bleed, and depressurizations are verified using the calculation. The results suggest that im- plementing feed and bleed and depressurization could be an effective way to arrest the severe accident sequences in PWR.
文摘Based on the analysis of construction project safety risk and its preventive measures, it is first necessary to clarify the safety risks and existing problems of construction project supervision and to formulate effective construction procedures. It is necessary to check the production safety of the construction unit, strengthen the company's own safety production management, and reasonably control the risk to familiarize with the construction drawings, and make a special construction plan for the work of the bottom line. Finally, an elective solution is drawn to comprehensively expound the importance of construction project construction safety risk and its preventive measures.
基金the support of the National Natural Science Foundation of China(U2240221,41977229)the Sichuan Youth Science and Technology Innovation Research Team Project(2020JDTD0006)the Sichuan Provincial International Science and Technology Collaboration&Innovation Project(2020YFH0092)。
文摘Numerous Quaternary deposits are existed in the mountainous areas of Southwest China,especially in the transition zone between the QinghaiTibet Plateau and the Sichuan Basin,where strong tectonic movements and frequent climatic changes increase the potential landslides.The possible deformation and failure process of potential landslides and their impacts on the surrounding environment are important research topics.Field investigation and monitoring indicate that the Qingliu landslide in Xiameng town,Li County,Sichuan Province,China has been continuously deforming since August 2020.The deformation zone has a maximum deformation depth of approximately 18.9m,a total area of 54,628 m2,and a volume of 34.0×104 m3,which seriously threatens infrastructure projects and dwellings.As a result,understanding the Qingliu landslide evolution process,assessing the hazard risk,and planning disaster prevention measures are of great significance for reducing disaster loss.In this study,the mass movement process and hazard risk of the Qingliu landslide are evaluated,and the effects of different prevention measures are compared and discussed.By using the depth-integrated method,the mass movement of the Qingliu landslide is analyzed.The numerical simulation results indicate that the maximum velocity of the Qingliu landslide is approximately 37.5 m/s,and the duration of the landslide is approximately 90s.The simulated landslide can eventually form a deposited mass with a maximum deposit thickness of 19.4 m and an area of approximately 60,168.3 m2,thereby blocking the river and burying dwellings.Furthermore,a risk assessment of the Qingliu landslide under different forms of protection measures is also produced and discussed by considering the hazard level and economic vulnerability level of the affected area.Setting three layers of anti-slide piles on the deformation zone to reduce the hazard risk of the Qingliu landslide is a better choice.Our results may be useful for planning prevention measures and improving disaster emergency response systems.