This paper reviews the history of coast evolution and coastal protection in the area of the abandoned Yellow River mouth in Jiangsu Province, analyzes the erosion characteristics and dynamic environment, evaluates the...This paper reviews the history of coast evolution and coastal protection in the area of the abandoned Yellow River mouth in Jiangsu Province, analyzes the erosion characteristics and dynamic environment, evaluates the efficiency of coastal protection engineering works and designs the dimensions of the main seadike and offshore submerged dam. A gerneral scheme of shore protection for this area is proposed.展开更多
The purpose of this paper is to develop a functional method for designing a series of submerged breakwaters on practical topography. The method is used to verify the feasibility and effectiveness of Bragg breakwaters ...The purpose of this paper is to develop a functional method for designing a series of submerged breakwaters on practical topography. The method is used to verify the feasibility and effectiveness of Bragg breakwaters for coastal protection by using field topography. The first part of this paper provides definitions and procedures needed in the design process for applying the mechanism of Bragg reflection. Next, Bragg breakwaters are designed on the basis of the cross-sectional topography and then on the plane topography of the Mi-Tuo coast by following the proposed process and procedure. Numerical modeling (Hsu et al., 2003; Wen and Tsai, 2008) was used as a design and assessment tool. Finally, the effectiveness and feasibility of a Bragg breakwater was assessed by practical cases. Based on the mechanism of Bragg reflection, an optimum layout for a series of submerged breakwaters is proposed to protect the Mi-Tuo coast. The results indicate that the proper layout of a series of submerged creakwaters can achieve the objective of beach protection.展开更多
Coastal change has merited attention because of heated arguments in the literature on this subject at national,regional,southern African,and international levels.The city of Maputo,the capital of Mozambique,which had ...Coastal change has merited attention because of heated arguments in the literature on this subject at national,regional,southern African,and international levels.The city of Maputo,the capital of Mozambique,which had been undergoing intense coastal erosion actions,was the target of large-scale intervention aimed at halting the advance of the sea and the consequent destruction of infrastructure.Coastal protection consisted of soft forms,artificial feeding,and heavy,longitudinal and transversal structures.This study was carried out along the protected line,about 3 km long,and aims to understand the morphological transformations in the Maputo city shoreline that occurred after the coastal protection.For that,the following technical methods were used:observation,a topographic survey of the beach cross-sections,and the shoreline evolution before and after coastal protection using 2008 and 2010 Google Earth satellite imagery prior to protection 2015,project completion year and 2018 monitoring year.The findings of the study revealed that the causes of coastal erosion persist,like constant removal by deflation of the borrowed sediment.Besides,vertical structures(groynes)intensify erosion in the downdrift while adherent structures interrupt the return of sediment deposited on the sidewalk and the road.The beach that experienced a positive sedimentary balance with artificial feeding has been losing more sediment than it gets.The transversal profiles show the beach shore has depressions that are submerged in the presence of high tides,bringing the sea closer to the adherent structure.Despite the sped up erosion observed,embryonic dunes were detected in some parts of the beach,signs of the establishment of dynamic equilibrium,becoming sites of sand accumulation and sediment source to the beach,through the exchange between the dune and the beach.With these results,a pilot station for artificial dune construction is being designed for beach stability.展开更多
China’s coastal line starts at the Yalu River in Liaoning in the north and ends at the Beilun River mouth in Guangxi. It is 18,000 kilometres long and crosses 11 provinces, municipalities and autonomous regions, incl...China’s coastal line starts at the Yalu River in Liaoning in the north and ends at the Beilun River mouth in Guangxi. It is 18,000 kilometres long and crosses 11 provinces, municipalities and autonomous regions, including Liaoning, Hebei, Tianjin, Shandong, Jiangsu, Shanghai, Zhejiang, Fujian, Guangdong, Guangxi and Hainan. In 1988, the Chinese government outlined the Coastal Protection Forest System Construction Project and defined the coastal line of 11 provinces as the main construction line. The project aims at developing a展开更多
This paper provides a comprehensive overview on coastal protection and hazard mitigation by mangroves.Previous stud-ies have made great strides to understand the mechanisms and influencing factors of mangroves’protec...This paper provides a comprehensive overview on coastal protection and hazard mitigation by mangroves.Previous stud-ies have made great strides to understand the mechanisms and influencing factors of mangroves’protection function,including wave energy dissipation,storm surge damping,tsunami mitigation,adjustment to sea level rise and wind speed reduction,which are sys-tematically summarized in this study.Moreover,the study analyzes the extensive physical models,based on indoor flume experi-ments and numerical models,that consider the interaction between mangroves and hydrodynamics,to help our understanding of mangrove-hydrodynamic interactions.Additionally,quantitative approaches for valuing coastal protection services provided by man-groves,including index-based and process-resolving approaches,are introduced in detail.Finally,we point out the limitations of previous studies,indicating that efforts are still required for obtaining more long-term field observations during extreme weather events,to create more real mangrove models for physical experiments,and to develop numerical models that consider the flexible properties of mangroves to better predict wave propagation in mangroves having complex morphology and structures.展开更多
A novel concept of wave attenuator is proposed for the defense of long waves,through integrating a flexible tail to the lee-side surface of a pile breakwater.The flexible tail works as a floating blanket made up of hi...A novel concept of wave attenuator is proposed for the defense of long waves,through integrating a flexible tail to the lee-side surface of a pile breakwater.The flexible tail works as a floating blanket made up of hinged blocks,whose scale and stiffness can be easily adjusted.A two-phase-flow numerical model is established based on the open-source computational fluid dynamics(CFD)code OpenFOAM to investigate its wave attenuation performance.Incompressible Navier−Stokes equations are solved in the fluid domain,where an additional computational solid mechanics(CSM)solver is embedded to describe the elastic deformation of the floating tail.The coupling of fluid dynamics and structural mechanics is solved in a full manner to allow assess of wave variation along the deforming body.The accuracy of the numerical model is validated through comparison with experimental data.Effects of the flexible tail on performance of the pile breakwater are investigated systematically.Dynamic behaviours of the tail are examined,and characteristics of its natural frequency are identified.For safety reasons,the wave loads impacting on the main body of the pile breakwater and the stress distribution over the tail are specially examined.It is found that both the length and stiffness of the tail can affect the wave-attenuation performance of the breakwater.A proper choice of the length and stiffness of the tail can greatly improve the long-wave defending capability of the pile breakwater.The maximum stress over the flexible tail can be restrained through optimising the deformation and stiffness of the tail.展开更多
-The effect of wave group on wave run-up on a slope dike is mainly discussed in this paper. Two simulating methods of wave group and their applications in laboratory are introduced. Synthesizing the research results o...-The effect of wave group on wave run-up on a slope dike is mainly discussed in this paper. Two simulating methods of wave group and their applications in laboratory are introduced. Synthesizing the research results of wave run-up on a slope dike, the effect of wave group on wave run-up on a slope dike in coastal protection engineering is studied as the main point.展开更多
Land for protective forest on the coast has special site conditions, and site classification is the scientific basis for seaboard afforestation. The site classification system on the coast zone and islands of China ma...Land for protective forest on the coast has special site conditions, and site classification is the scientific basis for seaboard afforestation. The site classification system on the coast zone and islands of China may be classified into five levels-site region (sub - region), district, class, group, and type. The land division for afforestation is carried out by the principle of enviornmental heterogeneity among regions, sub-region and district on large scale, according to the difference of air temperature, moisture and type of coast geomorphy. It may be classified into 7 regions, 12 sub-regions and 55 districts. The medium and small scaled division for site class, group and type, subdivided in a site district, are based on medium topography, topographic climate, micro - relief and soil conditions.展开更多
文摘This paper reviews the history of coast evolution and coastal protection in the area of the abandoned Yellow River mouth in Jiangsu Province, analyzes the erosion characteristics and dynamic environment, evaluates the efficiency of coastal protection engineering works and designs the dimensions of the main seadike and offshore submerged dam. A gerneral scheme of shore protection for this area is proposed.
文摘The purpose of this paper is to develop a functional method for designing a series of submerged breakwaters on practical topography. The method is used to verify the feasibility and effectiveness of Bragg breakwaters for coastal protection by using field topography. The first part of this paper provides definitions and procedures needed in the design process for applying the mechanism of Bragg reflection. Next, Bragg breakwaters are designed on the basis of the cross-sectional topography and then on the plane topography of the Mi-Tuo coast by following the proposed process and procedure. Numerical modeling (Hsu et al., 2003; Wen and Tsai, 2008) was used as a design and assessment tool. Finally, the effectiveness and feasibility of a Bragg breakwater was assessed by practical cases. Based on the mechanism of Bragg reflection, an optimum layout for a series of submerged breakwaters is proposed to protect the Mi-Tuo coast. The results indicate that the proper layout of a series of submerged creakwaters can achieve the objective of beach protection.
文摘Coastal change has merited attention because of heated arguments in the literature on this subject at national,regional,southern African,and international levels.The city of Maputo,the capital of Mozambique,which had been undergoing intense coastal erosion actions,was the target of large-scale intervention aimed at halting the advance of the sea and the consequent destruction of infrastructure.Coastal protection consisted of soft forms,artificial feeding,and heavy,longitudinal and transversal structures.This study was carried out along the protected line,about 3 km long,and aims to understand the morphological transformations in the Maputo city shoreline that occurred after the coastal protection.For that,the following technical methods were used:observation,a topographic survey of the beach cross-sections,and the shoreline evolution before and after coastal protection using 2008 and 2010 Google Earth satellite imagery prior to protection 2015,project completion year and 2018 monitoring year.The findings of the study revealed that the causes of coastal erosion persist,like constant removal by deflation of the borrowed sediment.Besides,vertical structures(groynes)intensify erosion in the downdrift while adherent structures interrupt the return of sediment deposited on the sidewalk and the road.The beach that experienced a positive sedimentary balance with artificial feeding has been losing more sediment than it gets.The transversal profiles show the beach shore has depressions that are submerged in the presence of high tides,bringing the sea closer to the adherent structure.Despite the sped up erosion observed,embryonic dunes were detected in some parts of the beach,signs of the establishment of dynamic equilibrium,becoming sites of sand accumulation and sediment source to the beach,through the exchange between the dune and the beach.With these results,a pilot station for artificial dune construction is being designed for beach stability.
文摘China’s coastal line starts at the Yalu River in Liaoning in the north and ends at the Beilun River mouth in Guangxi. It is 18,000 kilometres long and crosses 11 provinces, municipalities and autonomous regions, including Liaoning, Hebei, Tianjin, Shandong, Jiangsu, Shanghai, Zhejiang, Fujian, Guangdong, Guangxi and Hainan. In 1988, the Chinese government outlined the Coastal Protection Forest System Construction Project and defined the coastal line of 11 provinces as the main construction line. The project aims at developing a
基金funded by the National Key R&D Program of China(No.2023YFC3007900)the Young Scientists Fund of the National Natural Science Foundation of China(No.42106204)+2 种基金the Jiangsu Basic Research Program(Natural Science Foundation)(No.BK20220082)the National Natural Science Foundation of China(No.52271271)the Major Science&Technology Projects of the Ministry of Water Resources(No.SKS-2022025).
文摘This paper provides a comprehensive overview on coastal protection and hazard mitigation by mangroves.Previous stud-ies have made great strides to understand the mechanisms and influencing factors of mangroves’protection function,including wave energy dissipation,storm surge damping,tsunami mitigation,adjustment to sea level rise and wind speed reduction,which are sys-tematically summarized in this study.Moreover,the study analyzes the extensive physical models,based on indoor flume experi-ments and numerical models,that consider the interaction between mangroves and hydrodynamics,to help our understanding of mangrove-hydrodynamic interactions.Additionally,quantitative approaches for valuing coastal protection services provided by man-groves,including index-based and process-resolving approaches,are introduced in detail.Finally,we point out the limitations of previous studies,indicating that efforts are still required for obtaining more long-term field observations during extreme weather events,to create more real mangrove models for physical experiments,and to develop numerical models that consider the flexible properties of mangroves to better predict wave propagation in mangroves having complex morphology and structures.
基金financially supported by the National Natural Science Foundation of China(Grant No.51739010)the Natural Science Foundation of Liaoning Province(Grant No.2021-MS-122)+2 种基金the Special Project of Guangdong Science and Technology Department(Grant No.2021A05227)the Dalian Science and Technology Project(Grant No.2020RQ004)the Fundamental Research Funds for the Central Universities(Grant No.DUT22LAB128).
文摘A novel concept of wave attenuator is proposed for the defense of long waves,through integrating a flexible tail to the lee-side surface of a pile breakwater.The flexible tail works as a floating blanket made up of hinged blocks,whose scale and stiffness can be easily adjusted.A two-phase-flow numerical model is established based on the open-source computational fluid dynamics(CFD)code OpenFOAM to investigate its wave attenuation performance.Incompressible Navier−Stokes equations are solved in the fluid domain,where an additional computational solid mechanics(CSM)solver is embedded to describe the elastic deformation of the floating tail.The coupling of fluid dynamics and structural mechanics is solved in a full manner to allow assess of wave variation along the deforming body.The accuracy of the numerical model is validated through comparison with experimental data.Effects of the flexible tail on performance of the pile breakwater are investigated systematically.Dynamic behaviours of the tail are examined,and characteristics of its natural frequency are identified.For safety reasons,the wave loads impacting on the main body of the pile breakwater and the stress distribution over the tail are specially examined.It is found that both the length and stiffness of the tail can affect the wave-attenuation performance of the breakwater.A proper choice of the length and stiffness of the tail can greatly improve the long-wave defending capability of the pile breakwater.The maximum stress over the flexible tail can be restrained through optimising the deformation and stiffness of the tail.
文摘-The effect of wave group on wave run-up on a slope dike is mainly discussed in this paper. Two simulating methods of wave group and their applications in laboratory are introduced. Synthesizing the research results of wave run-up on a slope dike, the effect of wave group on wave run-up on a slope dike in coastal protection engineering is studied as the main point.
文摘Land for protective forest on the coast has special site conditions, and site classification is the scientific basis for seaboard afforestation. The site classification system on the coast zone and islands of China may be classified into five levels-site region (sub - region), district, class, group, and type. The land division for afforestation is carried out by the principle of enviornmental heterogeneity among regions, sub-region and district on large scale, according to the difference of air temperature, moisture and type of coast geomorphy. It may be classified into 7 regions, 12 sub-regions and 55 districts. The medium and small scaled division for site class, group and type, subdivided in a site district, are based on medium topography, topographic climate, micro - relief and soil conditions.