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2024,52(4):1-4 DOI: 10.3876/j.issn.1000-1980.2024.04.001
Abstract:
In order to improve the flood forecasting accuracy, the real-time online correction of the flood forecasting results by mining the measured water level and discharge data is used to make full use of the information contained in the measured sequences of water level and discharge. A Kalman filter correction technique is proposed based on multi-source forecast residuals. Corresponding rising difference model and autoregressive model were used to construct the multi-source error information source, and then Kalman filtering technology was used to fuse the multi-source error sequences for the real-time correction of flood forecast results. This paper selected the Qiantang River Basin of Zhejiang Province as the study area. The validation results show that the multi-source residual fusion correction technique based on Kalman filtering technology can significantly reduce the flow simulation error and the average relative error is reduced by more than 10%.
In order to improve the flood forecasting accuracy, the real-time online correction of the flood forecasting results by mining the measured water level and discharge data is used to make full use of the information contained in the measured sequences of water level and discharge. A Kalman filter correction technique is proposed based on multi-source forecast residuals. Corresponding rising difference model and autoregressive model were used to construct the multi-source error information source, and then Kalman filtering technology was used to fuse the multi-source error sequences for the real-time correction of flood forecast results. This paper selected the Qiantang River Basin of Zhejiang Province as the study area. The validation results show that the multi-source residual fusion correction technique based on Kalman filtering technology can significantly reduce the flow simulation error and the average relative error is reduced by more than 10%.
2024,52(4):5-12, 21 DOI: 10.3876/j.issn.1000-1980.2024.04.002
Abstract:
Based on the three-dimensional radar mosaic data from April to June in 2016-2019 and the differences in triggering conditions, a classification for warm-sector squall lines with vastly different formation mechanisms during the pre-flood season was proposed. They were divided into two types: squall lines that developed in the warm sector after frontal triggering(Type I warm-sector squall lines), and squall lines that were generated and developed in the warm sector(Type II warm-sector squall lines). On this basis, the distributions of short-term heavy rainfall and thunderstorm winds were compared in terms of large-scale environmental conditions and mesoscale radar echo characteristics during the occurrence of squall lines. The results showed that: Type I warm-sector squall lines were mostly formed in plain areas, while Type II warm-sector squall lines were mostly generated on the windward slopes of mountains and coastlines. Both squall lines were accompanied by obvious short-term heavy precipitation, which was easy to cause rainstorm and flood; Type I warm-sector squall lines were prone to producing regional thunderstorm winds, while Type II warm zone squall lines produce scattered thunderstorm winds. The Type I warm-sector squall lines had longer lifecycle, more vigorous convective development, and a faster moving speed, while the Type II warm-sector squall lines had shorter lifecycle and a slower moving speed with weaker echo intensity. Both types of squall lines had good water vapor conditions and vertical shear conditions of low-level winds at 0-3.km, and the dynamic and thermal conditions are better when Type I warm zone squall lines occurred.
Based on the three-dimensional radar mosaic data from April to June in 2016-2019 and the differences in triggering conditions, a classification for warm-sector squall lines with vastly different formation mechanisms during the pre-flood season was proposed. They were divided into two types: squall lines that developed in the warm sector after frontal triggering(Type I warm-sector squall lines), and squall lines that were generated and developed in the warm sector(Type II warm-sector squall lines). On this basis, the distributions of short-term heavy rainfall and thunderstorm winds were compared in terms of large-scale environmental conditions and mesoscale radar echo characteristics during the occurrence of squall lines. The results showed that: Type I warm-sector squall lines were mostly formed in plain areas, while Type II warm-sector squall lines were mostly generated on the windward slopes of mountains and coastlines. Both squall lines were accompanied by obvious short-term heavy precipitation, which was easy to cause rainstorm and flood; Type I warm-sector squall lines were prone to producing regional thunderstorm winds, while Type II warm zone squall lines produce scattered thunderstorm winds. The Type I warm-sector squall lines had longer lifecycle, more vigorous convective development, and a faster moving speed, while the Type II warm-sector squall lines had shorter lifecycle and a slower moving speed with weaker echo intensity. Both types of squall lines had good water vapor conditions and vertical shear conditions of low-level winds at 0-3.km, and the dynamic and thermal conditions are better when Type I warm zone squall lines occurred.
2024,52(4):13-21 DOI: 10.3876/j.issn.1000-1980.2024.04.003
Abstract:
To deeply and comprehensively explore the mechanism of the risk caused by dam break accident, this study proposes a calculation method of the risk caused by dam break accident through combining the mining of historical dam break accident cases and Bayesian network. Based on a large number of historical cases of dam break accidents at home and abroad, 24Model is used to identify and extract the causes and chain of dam break accidents. The topology structure caused by dam break accident is constructed, and the probability of dam break is calculated by Bayesian forward causal reasoning, and the mechanism of dam break is analyzed by reverse diagnostic reasoning. Based on the Bayesian sensitivity analysis, the key risk factors affecting dam failure are explored. The results show that in terms of human factors, the proportion of gate control problems is high, while in terms of management factors, construction problems, operation and maintenance management defects, and design problems are important indirect causes of dam break. Flood overtopping and seepage erosion/piping are the main risk factors leading to dam failure.
To deeply and comprehensively explore the mechanism of the risk caused by dam break accident, this study proposes a calculation method of the risk caused by dam break accident through combining the mining of historical dam break accident cases and Bayesian network. Based on a large number of historical cases of dam break accidents at home and abroad, 24Model is used to identify and extract the causes and chain of dam break accidents. The topology structure caused by dam break accident is constructed, and the probability of dam break is calculated by Bayesian forward causal reasoning, and the mechanism of dam break is analyzed by reverse diagnostic reasoning. Based on the Bayesian sensitivity analysis, the key risk factors affecting dam failure are explored. The results show that in terms of human factors, the proportion of gate control problems is high, while in terms of management factors, construction problems, operation and maintenance management defects, and design problems are important indirect causes of dam break. Flood overtopping and seepage erosion/piping are the main risk factors leading to dam failure.
2024,52(4):22-28 DOI: 10.3876/j.issn.1000-1980.2024.04.004
Abstract:
A three-dimensional seepage field analysis of the dam was carried out using the finite element numerical simulation, by taking the example of a 110 m-high asphalt concrete core rockfill dam. The research focuses on investigating the influence mechanism of different depths, lengths, and positions of cracks in the bottom gallery of the concrete faceplate dam on the dam’s seepage characteristics. The simulation results reveal that superficial cracks in gallery have little effect on the seepage field of dam, while the emergence of penetrating cracks at the top of the gallery significantly alters the distribution of the nearby seepage field and substantially increases the dam’s seepage volume. On the other hand, cracks at the bottom of the gallery have a relatively minor impact on the seepage volume. In regions where the tensile stress in the gallery exceeds the concrete’s tensile strength, multiple penetrating cracks tend to concentrate, leading to a rapid surge in seepage volume. This also triggers an increase in the permeability gradient within the strataand the transitional zone Ⅰ, warranting close attention.
A three-dimensional seepage field analysis of the dam was carried out using the finite element numerical simulation, by taking the example of a 110 m-high asphalt concrete core rockfill dam. The research focuses on investigating the influence mechanism of different depths, lengths, and positions of cracks in the bottom gallery of the concrete faceplate dam on the dam’s seepage characteristics. The simulation results reveal that superficial cracks in gallery have little effect on the seepage field of dam, while the emergence of penetrating cracks at the top of the gallery significantly alters the distribution of the nearby seepage field and substantially increases the dam’s seepage volume. On the other hand, cracks at the bottom of the gallery have a relatively minor impact on the seepage volume. In regions where the tensile stress in the gallery exceeds the concrete’s tensile strength, multiple penetrating cracks tend to concentrate, leading to a rapid surge in seepage volume. This also triggers an increase in the permeability gradient within the strataand the transitional zone Ⅰ, warranting close attention.
2024,52(4):29-34 DOI: 10.3876/j.issn.1000-1980.2024.04.005
Abstract:
In order to more accurately judge the loss of hydration heat inside the mass concrete during the casting process, a formula for the prediction of temperature distribution at the worst moment between surface and interior of concretes was established by considering six influencing factors, including the concrete adiabatic temperature rise, ambient temperature, casting temperature, heat dispersion coefficient of formwork material, heat dispersion coefficient of thermal insulation material and thickness of the casting layer. A damage calculation method of hydration heat was established based on the calibrated parameter from response surface analysis method, temperature distribution and Loland damage model, and then was verified by the finite element numerical model. The results show that the hydration heat damage equation can determine whether the damage cracking will be caused by temperature gradient at any point during the casting process.
In order to more accurately judge the loss of hydration heat inside the mass concrete during the casting process, a formula for the prediction of temperature distribution at the worst moment between surface and interior of concretes was established by considering six influencing factors, including the concrete adiabatic temperature rise, ambient temperature, casting temperature, heat dispersion coefficient of formwork material, heat dispersion coefficient of thermal insulation material and thickness of the casting layer. A damage calculation method of hydration heat was established based on the calibrated parameter from response surface analysis method, temperature distribution and Loland damage model, and then was verified by the finite element numerical model. The results show that the hydration heat damage equation can determine whether the damage cracking will be caused by temperature gradient at any point during the casting process.
2024,52(4):35-46 DOI: 10.3876/j.issn.1000-1980.2024.04.006
Abstract:
In order to investigate the underlying mechanism of ground collapse resulting from pipeline damage and soil leakage, a comprehensive analysis was conducted using the DEM-CFD method. This study considered various factors of ground collapse, including the pipeline burial depth, water pressure, and radius of damage openings, while examining two distinct working conditions, a single layer of sand and an overlying layer of clay. The obtained results reveal a clear positive correlation between the particle loss rate and the magnitude of ground settlement. The collapse process can be delineated into three distinct stages based on the particle loss rate that are particle migration, rapid loss, and gradual expansion of the settlement trough. Among the considered factors, water pressure emerged as the primary influencer of the particle loss rate. In the case of a single sandy soil layer, the particle loss rate demonstrates an increasing trend with higher water pressure, larger damage radius, and shallower burial depth. For the overlying clay layer, the duration of the particle migration phase positively correlates with the thickness of the overlying clay layer, while displaying a negative correlation with water pressure and damage opening radius.
In order to investigate the underlying mechanism of ground collapse resulting from pipeline damage and soil leakage, a comprehensive analysis was conducted using the DEM-CFD method. This study considered various factors of ground collapse, including the pipeline burial depth, water pressure, and radius of damage openings, while examining two distinct working conditions, a single layer of sand and an overlying layer of clay. The obtained results reveal a clear positive correlation between the particle loss rate and the magnitude of ground settlement. The collapse process can be delineated into three distinct stages based on the particle loss rate that are particle migration, rapid loss, and gradual expansion of the settlement trough. Among the considered factors, water pressure emerged as the primary influencer of the particle loss rate. In the case of a single sandy soil layer, the particle loss rate demonstrates an increasing trend with higher water pressure, larger damage radius, and shallower burial depth. For the overlying clay layer, the duration of the particle migration phase positively correlates with the thickness of the overlying clay layer, while displaying a negative correlation with water pressure and damage opening radius.
2024,52(4):47-55 DOI: 10.3876/j.issn.1000-1980.2024.04.007
Abstract:
In order to study the nonlinear hardening problem of three-dimensional complex structural materials, the consistent tangent modulus was introduced into the constitutive model considering the Von Mises plastic yield criterion and isotropic/kinematic hardening model, and the constitutive model was solved based on the scaled boundary finite element method (SBFEM) and balanced octree algorithm. The Newton Raphson iteration method was used to solve the elastic-plastic increment of displacement and stress. In order to reduce the computational complexity, the variables of the iteration process were only executed and stored at the proportional center point of the subdomain. At the same time, a solution program was developed using Fortran language. Two application examples show that the calculation results of the model have high accuracy.
In order to study the nonlinear hardening problem of three-dimensional complex structural materials, the consistent tangent modulus was introduced into the constitutive model considering the Von Mises plastic yield criterion and isotropic/kinematic hardening model, and the constitutive model was solved based on the scaled boundary finite element method (SBFEM) and balanced octree algorithm. The Newton Raphson iteration method was used to solve the elastic-plastic increment of displacement and stress. In order to reduce the computational complexity, the variables of the iteration process were only executed and stored at the proportional center point of the subdomain. At the same time, a solution program was developed using Fortran language. Two application examples show that the calculation results of the model have high accuracy.
2024,52(4):56-60, 69 DOI: 10.3876/j.issn.1000-1980.2024.04.008
Abstract:
In order to study the influence of position change of maintenance track on aerodynamic stability of structures, a long-span suspension bridge with closed steel box girder section is taken as the research object. The vortex vibration displacement response of the structure under different positions of maintenance tracks is obtained through the segmental model wind tunnel test. The computational fluid dynamics (CFD) method is used to simulate the flow field around the section under typical working conditions, and the internal mechanism of the influence of the maintenance track position on the vortex vibration characteristics of the section is further explored. The research results show that the location of the maintenance track has obvious influence on the vertical and torsional vortex vibration of the section. When the maintenance track is located at the middle or edge, the vortex vibration stability of the section will be deteriorated. Especially when the maintenance track is located at the edge, large amplitude torsional vibration will be induced. The numerical simulation results of the flow field show that the vortex vibration is mainly caused by the wake vortex shedding, and the change of the position of the maintenance track will change the size and position of the wake vortex shedding, thus further affecting the vortex vibration stability of the section. When the relative position of the track is 0.75, the vortex near the wake and repair track is weak and the flow field stability is optimal.
In order to study the influence of position change of maintenance track on aerodynamic stability of structures, a long-span suspension bridge with closed steel box girder section is taken as the research object. The vortex vibration displacement response of the structure under different positions of maintenance tracks is obtained through the segmental model wind tunnel test. The computational fluid dynamics (CFD) method is used to simulate the flow field around the section under typical working conditions, and the internal mechanism of the influence of the maintenance track position on the vortex vibration characteristics of the section is further explored. The research results show that the location of the maintenance track has obvious influence on the vertical and torsional vortex vibration of the section. When the maintenance track is located at the middle or edge, the vortex vibration stability of the section will be deteriorated. Especially when the maintenance track is located at the edge, large amplitude torsional vibration will be induced. The numerical simulation results of the flow field show that the vortex vibration is mainly caused by the wake vortex shedding, and the change of the position of the maintenance track will change the size and position of the wake vortex shedding, thus further affecting the vortex vibration stability of the section. When the relative position of the track is 0.75, the vortex near the wake and repair track is weak and the flow field stability is optimal.
2024,52(4):61-69 DOI: 10.3876/j.issn.1000-1980.2024.04.009
Abstract:
Sudden water pollution accidents may seriously affect the intake of water source, and the establishment of early warning stations is very important to protect the safety of water source. The existing research has not systematically discussed the determination method of early warning stations of water source in tidal river reach. Based on the coupled mathematical model of hydrodynamic and water quality in the Chengtong tidal reach of the Yangtze River, and on the basis of clarifying the law of diffusion and transport of pollutants in the reach under the combined action of channel and tide, the location and number of early warning stations in the Changqingsha and Langshan water sources were preliminarily established. Combined with the distribution characteristics of potential pollution sources and the accumulation characteristics of pollutants affecting the water source, the early warning station was checked in space, and the early warning station was checked in time by using the timeliness of early warning response. The locations of four early warning stations upstream and downstream of the two water sources were finally determined. Based on the correlation of water quality index between warning station and water source, the emergency response scheme of water source and the risk response limit value for phenol leakage in these two water sources were determined.
Sudden water pollution accidents may seriously affect the intake of water source, and the establishment of early warning stations is very important to protect the safety of water source. The existing research has not systematically discussed the determination method of early warning stations of water source in tidal river reach. Based on the coupled mathematical model of hydrodynamic and water quality in the Chengtong tidal reach of the Yangtze River, and on the basis of clarifying the law of diffusion and transport of pollutants in the reach under the combined action of channel and tide, the location and number of early warning stations in the Changqingsha and Langshan water sources were preliminarily established. Combined with the distribution characteristics of potential pollution sources and the accumulation characteristics of pollutants affecting the water source, the early warning station was checked in space, and the early warning station was checked in time by using the timeliness of early warning response. The locations of four early warning stations upstream and downstream of the two water sources were finally determined. Based on the correlation of water quality index between warning station and water source, the emergency response scheme of water source and the risk response limit value for phenol leakage in these two water sources were determined.
2024,52(4):70-77, 84 DOI: 10.3876/j.issn.1000-1980.2024.04.010
Abstract:
In order to solve the problems of the lack of design basis, low efficiency of artificial experience design and difficulty to maximize the wave dissipation of new multi-stage platform of ecological seawall, a three-dimensional mathematical model coupled with the high-precision capture algorithm of water-gas interface was built. Then, this model was used to study the wave dissipation characteristics and wave overtopping calculation of multi-stage platform of ecological seawall. Considering the overtopping laws of wave under different combinations of dike structure (step width, step height and dike height), a formula for calculating the wave overtopping of multi-stage platform of ecological seawall is put forward. The results show that with the gradual elevation of multi-stage platforms, the thickness of overlying water on the breakwater becomes smaller, resulting in the energy dissipation of continuous breaking of waves. At the same time, the multi-stage platforms block the propagation of shallow waves by stages, forcing the waves to reflect step by step and attenuate. The width and height of the multi-stage platform jointly control the overtopping of the breakwater. It is found that the longitudinal height and transverse width of the multi-stage platform have a quantitative exchange relationship under the same overtopping situation.
In order to solve the problems of the lack of design basis, low efficiency of artificial experience design and difficulty to maximize the wave dissipation of new multi-stage platform of ecological seawall, a three-dimensional mathematical model coupled with the high-precision capture algorithm of water-gas interface was built. Then, this model was used to study the wave dissipation characteristics and wave overtopping calculation of multi-stage platform of ecological seawall. Considering the overtopping laws of wave under different combinations of dike structure (step width, step height and dike height), a formula for calculating the wave overtopping of multi-stage platform of ecological seawall is put forward. The results show that with the gradual elevation of multi-stage platforms, the thickness of overlying water on the breakwater becomes smaller, resulting in the energy dissipation of continuous breaking of waves. At the same time, the multi-stage platforms block the propagation of shallow waves by stages, forcing the waves to reflect step by step and attenuate. The width and height of the multi-stage platform jointly control the overtopping of the breakwater. It is found that the longitudinal height and transverse width of the multi-stage platform have a quantitative exchange relationship under the same overtopping situation.
2024,52(4):78-84 DOI: 10.3876/j.issn.1000-1980.2024.04.011
Abstract:
This study focuses on the muddy-coastal headland bay beaches in Zhejiang Province, identifies the primary factors influencing the position of the sand-mud boundary, and analyses the transition mechanism. A depth formula of the sand-mud boundary point in headland bay beaches is proposed. The results show that: the tide level, wave height, beach slope and spring mean tide range in front of the beach are the main factors affecting the location of sand-mud boundary; the depth of sand-mud boundary is positively correlated with the 1/10 wave height in front of the beach and the spring mean tide range, and negatively correlated with the slope of the beach; the position of the sand-mud boundary exhibits seasonal and inter-annual variations. During summer, the sand-mud boundary tends to shift seaward and decrease in elevation, while in winter, it moves landward. Notably, in 2020, compared to 2019, the sand-mud boundary showed a clear trend of seaward migration and a decrease in elevation.
This study focuses on the muddy-coastal headland bay beaches in Zhejiang Province, identifies the primary factors influencing the position of the sand-mud boundary, and analyses the transition mechanism. A depth formula of the sand-mud boundary point in headland bay beaches is proposed. The results show that: the tide level, wave height, beach slope and spring mean tide range in front of the beach are the main factors affecting the location of sand-mud boundary; the depth of sand-mud boundary is positively correlated with the 1/10 wave height in front of the beach and the spring mean tide range, and negatively correlated with the slope of the beach; the position of the sand-mud boundary exhibits seasonal and inter-annual variations. During summer, the sand-mud boundary tends to shift seaward and decrease in elevation, while in winter, it moves landward. Notably, in 2020, compared to 2019, the sand-mud boundary showed a clear trend of seaward migration and a decrease in elevation.
2024,52(4):85-94 DOI: 10.3876/j.issn.1000-1980.2024.04.012
Abstract:
In order to explore the potential applications of nanofluidic materials in attenuating the dynamic response of pile-supported wharves and reducing their damages, this work built a two-dimensional finite element model of a pile-supported wharf with dampers using the open-source finite element platform OpenSees. The study compared the effects of conventional viscous dampers and nanofluidic dampers on the seismic performance of the pile-supported wharf. Results show that nanofluidic dampers have a better ability to limit the lateral deformation on the top of the piles than viscous dampers and are more effective than viscous dampers in reducing the curvature on the top of the land-side piles. The energy dissipation of pile top with nanofluidic dampers is lower than that of pile top with viscous dampers.
In order to explore the potential applications of nanofluidic materials in attenuating the dynamic response of pile-supported wharves and reducing their damages, this work built a two-dimensional finite element model of a pile-supported wharf with dampers using the open-source finite element platform OpenSees. The study compared the effects of conventional viscous dampers and nanofluidic dampers on the seismic performance of the pile-supported wharf. Results show that nanofluidic dampers have a better ability to limit the lateral deformation on the top of the piles than viscous dampers and are more effective than viscous dampers in reducing the curvature on the top of the land-side piles. The energy dissipation of pile top with nanofluidic dampers is lower than that of pile top with viscous dampers.
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2018,46(2):128-133, DOI: 10.3876/j.issn.1000-1980.2018.02.005
Abstract:
To improve the operational safety of earth rockfill dam, a longitudinal reinforcement is proposed. This rigid structure has triple functions as the seepage controlling, stress resistance and deformation resistance. Based on the classical mechanics, its anti-seepage effect, anti-deformation ability and the capacity to withstand external force is quantitatively analyzed. In addition, the quantitative relationships between the reinforcement thickness and the downstream water level, as well as the material properties of the rockfill dam are derived. For the theoretical derivation, the reinforced body is regarded as a fixed-end beam, loaded by water pressures from upstream and downstream, the active earth pressure from rockfill and the vertical drag force due to the differential settlement between core walls and rockfill. The top displacement together with the rotation angle and the bottom stress of the fixed end are derived from the deformation differential equation and validated through designing reviews. Subsequently, the construction method of buried steel pipe, which is adopted to perform the base grouting and also to meet the strength requirements, is put forward. The proposed method plays an important guiding role in rehabilitating and reinforcing the dangerous earth rockfill dams, as well as the design and construction of new dams.
To improve the operational safety of earth rockfill dam, a longitudinal reinforcement is proposed. This rigid structure has triple functions as the seepage controlling, stress resistance and deformation resistance. Based on the classical mechanics, its anti-seepage effect, anti-deformation ability and the capacity to withstand external force is quantitatively analyzed. In addition, the quantitative relationships between the reinforcement thickness and the downstream water level, as well as the material properties of the rockfill dam are derived. For the theoretical derivation, the reinforced body is regarded as a fixed-end beam, loaded by water pressures from upstream and downstream, the active earth pressure from rockfill and the vertical drag force due to the differential settlement between core walls and rockfill. The top displacement together with the rotation angle and the bottom stress of the fixed end are derived from the deformation differential equation and validated through designing reviews. Subsequently, the construction method of buried steel pipe, which is adopted to perform the base grouting and also to meet the strength requirements, is put forward. The proposed method plays an important guiding role in rehabilitating and reinforcing the dangerous earth rockfill dams, as well as the design and construction of new dams.
2019,47(1):1-6, DOI: 10.3876/j.issn.1000-1980.2019.01.001
Abstract:
To improve the accuracy of flood forecasting, 13 flood events between 2000 and 2017 were selected from the sections of Lutaizi and Lubeng, and the Xin’anjiang three-source model(XAJ model)was used to simulate the flood events. The Lutaizi basin can be divided into 9 natural sub-basins and the Lubeng basin can be divided into 4 natural sub-basins. Then, the XAJ model was calibrated for these basins. The node generalizability was carried out in the mainstream section of the Huaihe River with flood diversion and flood retarding areas. Combined with the diversion ratio method and the Muskingen method, the simulation method of flood diversion was established, and fairly good forecasting results were obtained. The research results show that: for the relative error of flood volume, the qualified rates of Lutaizi and Lubeng region are both up to 100%, and the Lutaizi reached a qualified rate of 100% in the flood peak, while the Lubeng region reached 92. 3%. In two floods in 2003 and 2007, the relative error and the certainty coefficient of flood peak have been significantly improved.
To improve the accuracy of flood forecasting, 13 flood events between 2000 and 2017 were selected from the sections of Lutaizi and Lubeng, and the Xin’anjiang three-source model(XAJ model)was used to simulate the flood events. The Lutaizi basin can be divided into 9 natural sub-basins and the Lubeng basin can be divided into 4 natural sub-basins. Then, the XAJ model was calibrated for these basins. The node generalizability was carried out in the mainstream section of the Huaihe River with flood diversion and flood retarding areas. Combined with the diversion ratio method and the Muskingen method, the simulation method of flood diversion was established, and fairly good forecasting results were obtained. The research results show that: for the relative error of flood volume, the qualified rates of Lutaizi and Lubeng region are both up to 100%, and the Lutaizi reached a qualified rate of 100% in the flood peak, while the Lubeng region reached 92. 3%. In two floods in 2003 and 2007, the relative error and the certainty coefficient of flood peak have been significantly improved.
2020,48(1):1-7, DOI: 10.3876/j.issn.1000-1980.2020.01.001
Abstract:
Based on the development of hydrology science and the basic framework of physical and virtual water coupled flow theory, this study indicated that the process hydrology is an interdiscipline that can reveal the coupled flow law and associated effects of physical and virtual water in complicated system. In addition, this study makes a detailed analysis of the scientific connotation, main characteristics, framework, discipline basis, method system and core tasks of process hydrology. Given the theoretical value and practical significance of process hydrology, it can be concluded that the development of process hydrology can provide measures and new views to cope with new challenges in hydrology that the sustainable developments of nature, economy and society faces.
Based on the development of hydrology science and the basic framework of physical and virtual water coupled flow theory, this study indicated that the process hydrology is an interdiscipline that can reveal the coupled flow law and associated effects of physical and virtual water in complicated system. In addition, this study makes a detailed analysis of the scientific connotation, main characteristics, framework, discipline basis, method system and core tasks of process hydrology. Given the theoretical value and practical significance of process hydrology, it can be concluded that the development of process hydrology can provide measures and new views to cope with new challenges in hydrology that the sustainable developments of nature, economy and society faces.
2021,49(1):1-6, DOI: 10. 3876/ j. issn.1000-1980.2021.01.001
Abstract:
This study introduces the basic situation of China‘s small and medium-sized rivers and flood disasters, and then key difficulties as well as urgent scientific and technological problems in the flood prevention of small and medium-sized rivers were analyzed. Thereafter, the study puts forward the strategy and measures for the flood forecasting and early warning of small and medium- sized rivers. Besides, prospects for the future forecasting, risk early warning, and refined risk management concepts and practices are also proposed. It will realize the change from the hydrological element forecasting to the flood impact forecasting, from the flood threshold-based warning to the flood risk warning, from the " prediction-response" emergency disposal to the grid refinement risk management, from the monitoring data provision to the information product service, in which the development level of the hydrological modernization is continuously improved.
This study introduces the basic situation of China‘s small and medium-sized rivers and flood disasters, and then key difficulties as well as urgent scientific and technological problems in the flood prevention of small and medium-sized rivers were analyzed. Thereafter, the study puts forward the strategy and measures for the flood forecasting and early warning of small and medium- sized rivers. Besides, prospects for the future forecasting, risk early warning, and refined risk management concepts and practices are also proposed. It will realize the change from the hydrological element forecasting to the flood impact forecasting, from the flood threshold-based warning to the flood risk warning, from the " prediction-response" emergency disposal to the grid refinement risk management, from the monitoring data provision to the information product service, in which the development level of the hydrological modernization is continuously improved.
2020,48(1):22-28, DOI: 10.3876/j.issn.1000-1980.2020.01.004
Abstract:
This study reviewed the environmental behavior of microplastics(including the adsorption of organic pollutants and the release of organic additives after entering water), and the interaction between microplastics and organic pollutants after entering into water body, including its mechanism, influencing factors and biological toxicity. It also analyzed the deficiencies of current researches, and believed that, in order to provide theoretical basis for further study on the behavior and function of microplastics, it is necessary to expand the research on the interaction between microplastics and organic pollutants, such as strengthening the research in the freshwater environment, establishing systematic research system, and paying attention to the effect of biofilm
This study reviewed the environmental behavior of microplastics(including the adsorption of organic pollutants and the release of organic additives after entering water), and the interaction between microplastics and organic pollutants after entering into water body, including its mechanism, influencing factors and biological toxicity. It also analyzed the deficiencies of current researches, and believed that, in order to provide theoretical basis for further study on the behavior and function of microplastics, it is necessary to expand the research on the interaction between microplastics and organic pollutants, such as strengthening the research in the freshwater environment, establishing systematic research system, and paying attention to the effect of biofilm
2020,48(2):95-101, DOI: 10.3876/j.issn.1000-1980.2020.02.001
Abstract:
Although the Piecewise Muskingum method for river flood calculation has been widely used in China, the major limitation that hinders the further application of the Piecewise Muskingum method within distributed models still needs to be addressed. This method with empirical parameters cannot consider the impact of changing river cross-section characteristics and hydraulic roughness on the flood computation. In this study, the Muskingum-Cunge-Todini variable parameter method and the non-linear reservoir method, which could consider the channel cross-section geometry and hydraulic roughness, were used in the river flood calculation in the middle part of Huaihe river, from Wujiadu to Xiaoliuxiang, and the middle part of Hutuo River, from Huangbizhuang to Beizhongshan. In addition, the river flood calculation with the Piecewise Muskingum method also has been conducted as a comparison. Initial tests indicate that the Muskingum-Cunge-Todini variable parameter method and the non-linear reservoir method have high simulation accuracy in the studied cases. The correct rate of flood peak is above 86%, and the coefficient of certainty is greater than 0. 8. This study can provide references for the flood calculation considering the change of the channel cross section and hydraulic roughness characteristics.
Although the Piecewise Muskingum method for river flood calculation has been widely used in China, the major limitation that hinders the further application of the Piecewise Muskingum method within distributed models still needs to be addressed. This method with empirical parameters cannot consider the impact of changing river cross-section characteristics and hydraulic roughness on the flood computation. In this study, the Muskingum-Cunge-Todini variable parameter method and the non-linear reservoir method, which could consider the channel cross-section geometry and hydraulic roughness, were used in the river flood calculation in the middle part of Huaihe river, from Wujiadu to Xiaoliuxiang, and the middle part of Hutuo River, from Huangbizhuang to Beizhongshan. In addition, the river flood calculation with the Piecewise Muskingum method also has been conducted as a comparison. Initial tests indicate that the Muskingum-Cunge-Todini variable parameter method and the non-linear reservoir method have high simulation accuracy in the studied cases. The correct rate of flood peak is above 86%, and the coefficient of certainty is greater than 0. 8. This study can provide references for the flood calculation considering the change of the channel cross section and hydraulic roughness characteristics.
2019,47(1):7-12, DOI: 10.3876/j.issn.1000-1980.2019.01.002
Abstract:
In order to make full use of the continues pumping test data to estimate the hydraulic conductivity(K), the transmissivity(T)and the storage coefficient(μ*)of different head depression cones in a confined aquifer, a dimensionless analytical solution of drawdown transients with variable pumping rates was derived based on the Theis formula and the principle of superposition. Furthermore, a new type curve method was proposed. The in-situ pumping test was conducted to obtain the drawdown record perturbed by stepwise rates. Then, the drawdown curve was used to match the corresponding type curve. After that, this method selects one match point and records its coordinate values on both the type curve and the real drawdown curve. By substituting these recorded values into related formulas, the hydraulic parameters of the confined aquifer can be determined. This method was applied to a field pumping test conducted at a southern highway in Wuxi, Jiangsu Province, China. The type curve matching process is implemented in stages. Field test results reveal that the hydraulic conductivity of the confined aquifer with the 2-3 silt layer are 5. 12×10-4 cm/s, 2. 54×10-3 cm/s and 2. 83×10-3 cm/s respectively, which are corresponding to three-stage stepwise pumping rates.
In order to make full use of the continues pumping test data to estimate the hydraulic conductivity(K), the transmissivity(T)and the storage coefficient(μ*)of different head depression cones in a confined aquifer, a dimensionless analytical solution of drawdown transients with variable pumping rates was derived based on the Theis formula and the principle of superposition. Furthermore, a new type curve method was proposed. The in-situ pumping test was conducted to obtain the drawdown record perturbed by stepwise rates. Then, the drawdown curve was used to match the corresponding type curve. After that, this method selects one match point and records its coordinate values on both the type curve and the real drawdown curve. By substituting these recorded values into related formulas, the hydraulic parameters of the confined aquifer can be determined. This method was applied to a field pumping test conducted at a southern highway in Wuxi, Jiangsu Province, China. The type curve matching process is implemented in stages. Field test results reveal that the hydraulic conductivity of the confined aquifer with the 2-3 silt layer are 5. 12×10-4 cm/s, 2. 54×10-3 cm/s and 2. 83×10-3 cm/s respectively, which are corresponding to three-stage stepwise pumping rates.
2020,48(3):189-194, DOI: 10.3876/j.issn.1000-1980.2020.03.001
Abstract:
On the basis of the original Xin’anjiang model, this study solved the matching problem between sub-catchment and grid channel, and enabled the model to calculate channel routing according to actual river conditions. A hybrid rainfall-runoff model(named XAJ-DCH)was further proposed by coupling the XAJ model with diffusion wave method and Muskingum-Cunge-Todini(MCT)method by accounting for the lateral inflow. The flood prediction capabilities of the traditional XAJ model and the XAJ-DCH model were compared at hourly scale for the Chengcun catchment. The performance of both models is comparable and satisfactory, and thus, the rationality of the new model is verified. By improving the channel routing method in the Xin’anjiang model, the spatiotemporal variability can be further considered. Furthermore, compared with the Xin’anjiang model, the XAJ-DCH model can not only be used to simulate the discharge at the outlet station, but also to predict the water level and discharge of the interior station in the catchment. In addition, the diffusion wave method was introduced into the XAJ-DCH model, which can improve the prediction accuracy in hydraulically mild slope area by accounting for the backwater effects.
On the basis of the original Xin’anjiang model, this study solved the matching problem between sub-catchment and grid channel, and enabled the model to calculate channel routing according to actual river conditions. A hybrid rainfall-runoff model(named XAJ-DCH)was further proposed by coupling the XAJ model with diffusion wave method and Muskingum-Cunge-Todini(MCT)method by accounting for the lateral inflow. The flood prediction capabilities of the traditional XAJ model and the XAJ-DCH model were compared at hourly scale for the Chengcun catchment. The performance of both models is comparable and satisfactory, and thus, the rationality of the new model is verified. By improving the channel routing method in the Xin’anjiang model, the spatiotemporal variability can be further considered. Furthermore, compared with the Xin’anjiang model, the XAJ-DCH model can not only be used to simulate the discharge at the outlet station, but also to predict the water level and discharge of the interior station in the catchment. In addition, the diffusion wave method was introduced into the XAJ-DCH model, which can improve the prediction accuracy in hydraulically mild slope area by accounting for the backwater effects.
2017,45(3):277-282, DOI: 10.3876/j.issn.1000-1980.2017.03.014
Abstract:
It is necessary to monitor the state of ZnO arresters to guarantee their safe operation. In order to select a best way to monitor the state of arresters, the advantages, disadvantages, and application of each monitoring method were analyzed. The results show that the harmonic analysis method is the most effective method. The properties of the harmonic analysis method in practical application could be improved by modifying the resistive leakage current and selecting an appropriate window function when conducting fast discrete Fourier transform on the collected signals. Through review of monitoring technologies in China and abroad, it can be found that in the future, the overall development trend of online monitoring methods of ZnO arresters is to develop fully automatic and multi-functional integrated online insulation monitoring systems.
It is necessary to monitor the state of ZnO arresters to guarantee their safe operation. In order to select a best way to monitor the state of arresters, the advantages, disadvantages, and application of each monitoring method were analyzed. The results show that the harmonic analysis method is the most effective method. The properties of the harmonic analysis method in practical application could be improved by modifying the resistive leakage current and selecting an appropriate window function when conducting fast discrete Fourier transform on the collected signals. Through review of monitoring technologies in China and abroad, it can be found that in the future, the overall development trend of online monitoring methods of ZnO arresters is to develop fully automatic and multi-functional integrated online insulation monitoring systems.
2015,43(5):384-394, DOI: 10.3876/j.issn.1000-1980.2015.05.002
Abstract:
Water resources constraints constitute a significant bottleneck in China. The origins of water are worth further research, as they relate to the Earth’s formation, the origins of the water globe, and the issue of deep water. First, we attempt to divide the hydrosphere into several belts and focus on the complex interaction between spherical layers. Then, water resources development issues are discussed, the concept of the comprehensive effect and related evaluation of the evolution of an entire basin is developed based on the spherical layer movement, and the evolution of the middle reaches of the Yellow River, the middle and upper reaches of the Yangtze River, and the inland river basin is analyzed based on this concept. Water resources development should consider three properties: limits, relativity, and ecology, as well as the instructive observation that water can carry a boat and also overturn a boat. The comprehensive development and utilization of water from six different sources, including rainwater, river water, lake water, groundwater, reservoir water, and sea water, are examined. We also discuss prevention and mitigation of six types of disasters related to the six water sources: flooding, waterlogging, drought, storm surges, geological disasters, and water pollution. It is pointed out that segmented control of water quality in the reservoir area, comprehensive development of surface water and groundwater, and construction of underground reservoirs are important. Finally, some suggestions for water resources development and disaster prevention are proposed: cooperation between multiple departments and multiple disciplines, implementation of water-saving measures, construction of an enhanced water resources network, determination of demand according to provision, and improvement of an investigation system for evaluation and development.
Water resources constraints constitute a significant bottleneck in China. The origins of water are worth further research, as they relate to the Earth’s formation, the origins of the water globe, and the issue of deep water. First, we attempt to divide the hydrosphere into several belts and focus on the complex interaction between spherical layers. Then, water resources development issues are discussed, the concept of the comprehensive effect and related evaluation of the evolution of an entire basin is developed based on the spherical layer movement, and the evolution of the middle reaches of the Yellow River, the middle and upper reaches of the Yangtze River, and the inland river basin is analyzed based on this concept. Water resources development should consider three properties: limits, relativity, and ecology, as well as the instructive observation that water can carry a boat and also overturn a boat. The comprehensive development and utilization of water from six different sources, including rainwater, river water, lake water, groundwater, reservoir water, and sea water, are examined. We also discuss prevention and mitigation of six types of disasters related to the six water sources: flooding, waterlogging, drought, storm surges, geological disasters, and water pollution. It is pointed out that segmented control of water quality in the reservoir area, comprehensive development of surface water and groundwater, and construction of underground reservoirs are important. Finally, some suggestions for water resources development and disaster prevention are proposed: cooperation between multiple departments and multiple disciplines, implementation of water-saving measures, construction of an enhanced water resources network, determination of demand according to provision, and improvement of an investigation system for evaluation and development.
2020,48(4):377-384, DOI: 10.3876/j.issn.1000-1980.2020.04.013
Abstract:
Firstly, the necessity of power electronization is explained from the development history of the power electronics and the challenges in power generation, transmission, distribution, and consumption. Secondly, the driving factors of power electronization, such as politics, economy, and technology, are elaborated in three aspects, including energy security and political construction, the resource and environmental benefits, and the transformation of power generation, transmission, distribution and consumption. Finally, the development trends and main restrictive factors of power electronization in power system are analyzed, and related study directions are summarized to provide some references and suggestions for future study.
Firstly, the necessity of power electronization is explained from the development history of the power electronics and the challenges in power generation, transmission, distribution, and consumption. Secondly, the driving factors of power electronization, such as politics, economy, and technology, are elaborated in three aspects, including energy security and political construction, the resource and environmental benefits, and the transformation of power generation, transmission, distribution and consumption. Finally, the development trends and main restrictive factors of power electronization in power system are analyzed, and related study directions are summarized to provide some references and suggestions for future study.
2020,48(2):102-108, DOI: 10.3876/j.issn.1000-1980.2020.02.002
Abstract:
In order to obtain the characteristics of wind field and flow field as well as the influence of different types of wind fields on the flow field of Taihu Lake, 6 acoustic doppler current profilers(ADCP)and 4 meteorological stations were set up in different areas of Taihu Lake, and the synchronous data of flow field and wind field were obtained. The results show the floolwing: (a)The spatial distribution of wind field in Taihu Lake was not uniform, the wind speed varied greatly among 4 stations, and the difference of wind direction was expanded along with the decrease of wind speed. (b)The flow field in Taihu Lake had obvious characteristics of wind-generated flow. When the average wind speed was greater than 6. 7 m/s, there was a counterclockwise circulation that appeared in the western lake area, and there was no obvious flow stratification during this period. When the average wind speed was less than 3. 8 m/s, the circulation in the west fade away. However, the flow stratification was obviously developed, the current direction of each layer was relatively stable but different, and the compensation flow developed. (c)According to the observed data, the percentage of current speed less than 10 cm/s was more than 90%, and the current speed can reach 20 cm/s under strong wind conditions.
In order to obtain the characteristics of wind field and flow field as well as the influence of different types of wind fields on the flow field of Taihu Lake, 6 acoustic doppler current profilers(ADCP)and 4 meteorological stations were set up in different areas of Taihu Lake, and the synchronous data of flow field and wind field were obtained. The results show the floolwing: (a)The spatial distribution of wind field in Taihu Lake was not uniform, the wind speed varied greatly among 4 stations, and the difference of wind direction was expanded along with the decrease of wind speed. (b)The flow field in Taihu Lake had obvious characteristics of wind-generated flow. When the average wind speed was greater than 6. 7 m/s, there was a counterclockwise circulation that appeared in the western lake area, and there was no obvious flow stratification during this period. When the average wind speed was less than 3. 8 m/s, the circulation in the west fade away. However, the flow stratification was obviously developed, the current direction of each layer was relatively stable but different, and the compensation flow developed. (c)According to the observed data, the percentage of current speed less than 10 cm/s was more than 90%, and the current speed can reach 20 cm/s under strong wind conditions.
2015,43(4):288-293, DOI: 10.3876/j.issn.1000-1980.2015.04.002
Abstract:
Considering the hydrological calculation and prediction of ungauged basins, a distributed hydrological model, the THREW model, was adopted to study the upper basin of the Brahmaputra River from the Nuxia Hydrological Station. Surface meteorological observation, remote sensing of vegetation cover, snow cover area, and section hydrological monitoring data were used to calibrate the model, and the latest CMIP5 data were used to estimate the runoff evolution. The results showed that, in the upper basin of the Brahmaputra River from the Nuxia Hydrological Station, the Nash-Sutcliffe efficiency coefficient of monthly runoff simulation of the calibration period from 1991 to 1995 was 0. 75, the coefficient of monthly runoff simulation of the validation period from 1996 to 2000 was 0. 76, and the runoff markedly increased when the CO2 discharge in the AR5 of IPCC was maximal.
Considering the hydrological calculation and prediction of ungauged basins, a distributed hydrological model, the THREW model, was adopted to study the upper basin of the Brahmaputra River from the Nuxia Hydrological Station. Surface meteorological observation, remote sensing of vegetation cover, snow cover area, and section hydrological monitoring data were used to calibrate the model, and the latest CMIP5 data were used to estimate the runoff evolution. The results showed that, in the upper basin of the Brahmaputra River from the Nuxia Hydrological Station, the Nash-Sutcliffe efficiency coefficient of monthly runoff simulation of the calibration period from 1991 to 1995 was 0. 75, the coefficient of monthly runoff simulation of the validation period from 1996 to 2000 was 0. 76, and the runoff markedly increased when the CO2 discharge in the AR5 of IPCC was maximal.
Journal information
- Competent unit：
Ministry of Education, P. R.China
- Organizers：
Hohai University
- Editor-in-chief：
TANG Hongwu
- Address：
1 Xikang Road, Nanjing 210098, P.R. China
- Postcode：
210098
- Phone：
86-25-83786343
- Email：
xb@hhu.edu.cn
- CN：
32-1117/TV
- ISSN：
1000-1980
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Journal of Hohai University (Natural Sciences) ® 2025 All Rights ReservedAddress：1 Xikang Road, Nanjing 210098, P.R. ChinaPostcode：210098Tel：86-25-83786343
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