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2023,43(2):1-8, 26 DOI: 10.3880/j.issn.1006-7647.2023.02.001
Abstract:
Based on the principle of local scour of bridge piers, and on the basis of the anti-scour measures of horizontal collars, a new anti-scour protection measure, called ridged collar, which can change the water flow around the piers was designed. In order to explore the protective effect of the ridged collar on the local scour of cylindrical bridge piers, indoor physical model tests were conducted using ridged collars of different shapes, and the scour characteristics and hydraulic properties around the pier were studied. The test results show that, the protection effect is the best for a ridged collar installed on the bed surface with a height of 1 cm and an angle of 135°. Compared with cases of no protective measures, after the ridged collar is installed on the bridge pier, the maximum scour depth reduction can reach 62.2%, and the vertical flow velocity and vertical turbulence intensity at the bottom of the pier can be significantly reduced. Through multivariate analysis, an empirical equation for calculating the non-dimensional maximum scour depth around the pier is established, which is applicable to both open channel flows and flows under ice sheet.
Based on the principle of local scour of bridge piers, and on the basis of the anti-scour measures of horizontal collars, a new anti-scour protection measure, called ridged collar, which can change the water flow around the piers was designed. In order to explore the protective effect of the ridged collar on the local scour of cylindrical bridge piers, indoor physical model tests were conducted using ridged collars of different shapes, and the scour characteristics and hydraulic properties around the pier were studied. The test results show that, the protection effect is the best for a ridged collar installed on the bed surface with a height of 1 cm and an angle of 135°. Compared with cases of no protective measures, after the ridged collar is installed on the bridge pier, the maximum scour depth reduction can reach 62.2%, and the vertical flow velocity and vertical turbulence intensity at the bottom of the pier can be significantly reduced. Through multivariate analysis, an empirical equation for calculating the non-dimensional maximum scour depth around the pier is established, which is applicable to both open channel flows and flows under ice sheet.
2023,43(2):9-15, 38 DOI: 10.3880/j.issn.1006-7647.2023.02.002
Abstract:
In order to study the impacts of different width-depth ratios and radius-width ratios on the hydrodynamic characteristics at open-channel confluences with bend flow, a three-dimensional numerical model was established by using the volume of fluid (VOF) method for the free surface capture and adopting the RNG k-ε model for the governing equations closure. The water surface pattern, velocity distribution, secondary flow and shape of separation zone were analyzed after the simulations of five combined cases with three width-depth ratios and three radius-width ratios. The results indicate that the degree of water level drop near the intersection decreases with the increase of the width-depth ratio or the decrease of the radius-width ratio. Compared to the radius-width ratio, the width-depth ratio has a stronger impact on the non-uniformity of velocity distribution at the confluence and the downstream area. When the width-depth ratio increases, the longitudinal flow rate increases and the non-uniformity of velocity distribution increases with enhanced flow deflection effect. When the width-depth ratio or radius-width ratio increases, the reflux structure at the bend is enhanced, the size of the separation zone increases with narrower and longer horizontal form.
In order to study the impacts of different width-depth ratios and radius-width ratios on the hydrodynamic characteristics at open-channel confluences with bend flow, a three-dimensional numerical model was established by using the volume of fluid (VOF) method for the free surface capture and adopting the RNG k-ε model for the governing equations closure. The water surface pattern, velocity distribution, secondary flow and shape of separation zone were analyzed after the simulations of five combined cases with three width-depth ratios and three radius-width ratios. The results indicate that the degree of water level drop near the intersection decreases with the increase of the width-depth ratio or the decrease of the radius-width ratio. Compared to the radius-width ratio, the width-depth ratio has a stronger impact on the non-uniformity of velocity distribution at the confluence and the downstream area. When the width-depth ratio increases, the longitudinal flow rate increases and the non-uniformity of velocity distribution increases with enhanced flow deflection effect. When the width-depth ratio or radius-width ratio increases, the reflux structure at the bend is enhanced, the size of the separation zone increases with narrower and longer horizontal form.
2023,43(2):16-26 DOI: 10.3880/j.issn.1006-7647.2023.02.003
Abstract:
To investigate the process of pollutant transport in sinuous open channel flow, a 3D hydrodynamic-pollutant coupled large-eddy simulation model was established according to the scalar tracer experiment. The influence of different release positions in transverse and vertical directions of point source on the concentration distribution in the downstream was analyzed. The results show that the streamwise velocity, vorticity and turbulent kinetic energy have clear relations and the secondary currents exert dominant impact on transport and mixing. Besides, the variance in transverse and vertical position of point source has significant influence on mixing efficiency and spatial distribution of pollutant. Specifically, the point source placed near the center of cross section in transverse direction or near the bottom of channel in vertical direction will result in a higher mixing efficiency and a wider influence range. There exists a positive correlation relationship between mixing rate and distribution range in the near field. The variance of point source position in a sinuous open channel mainly influences the pollutant’s mixing within a single period.
To investigate the process of pollutant transport in sinuous open channel flow, a 3D hydrodynamic-pollutant coupled large-eddy simulation model was established according to the scalar tracer experiment. The influence of different release positions in transverse and vertical directions of point source on the concentration distribution in the downstream was analyzed. The results show that the streamwise velocity, vorticity and turbulent kinetic energy have clear relations and the secondary currents exert dominant impact on transport and mixing. Besides, the variance in transverse and vertical position of point source has significant influence on mixing efficiency and spatial distribution of pollutant. Specifically, the point source placed near the center of cross section in transverse direction or near the bottom of channel in vertical direction will result in a higher mixing efficiency and a wider influence range. There exists a positive correlation relationship between mixing rate and distribution range in the near field. The variance of point source position in a sinuous open channel mainly influences the pollutant’s mixing within a single period.
2023,43(2):27-32 DOI: 10.3880/j.issn.1006-7647.2023.02.004
Abstract:
To deeply analyze the influence factors of ship lift deformation, a method for building ship lift deformation monitoring model based on quantile regression is proposed. Based on the structural characteristics of the ship lift, the influence factors such as air temperature and mean value of upstream water level in early stages are introduced into the candidate influence factor set. Adaptive elastic net penalized quantile regression is used for choosing the influence factors of ship lift deformation and building the quantile regression model. The optimal model can be obtained based on the principle of good fitting and validity check. Example verification shows that compared with traditional stepwise regression model, the proposed optimized model has low volatility for prediction accuracy with strong stability, indication a good ability for long term prediction.
To deeply analyze the influence factors of ship lift deformation, a method for building ship lift deformation monitoring model based on quantile regression is proposed. Based on the structural characteristics of the ship lift, the influence factors such as air temperature and mean value of upstream water level in early stages are introduced into the candidate influence factor set. Adaptive elastic net penalized quantile regression is used for choosing the influence factors of ship lift deformation and building the quantile regression model. The optimal model can be obtained based on the principle of good fitting and validity check. Example verification shows that compared with traditional stepwise regression model, the proposed optimized model has low volatility for prediction accuracy with strong stability, indication a good ability for long term prediction.
2023,43(2):33-38 DOI: 10.3880/j.issn.1006-7647.2023.02.005
Abstract:
To reveal the influence of delayed-peak rainfall infiltration on ultimate bearing capacity of an unsaturated foundation rapidly, the following research work was carried out. The Gardner’s permeability coefficient function and the soil-water characteristic curve model were introduced to simplify the Richards unsaturated seepage control equation, and the Laplace transform was adopted to derive the transient analytical solution of matrix suction for foundation under delayed-peak rainfall infiltration with rain intensity, which was verified with the finite element numerical simulation results. Based on the theory of shear strength for unsaturated soil and the transient analytical solution of matrix suction, the expression of transient ultimate bearing capacity for foundation was obtained under delayed-peak rainfall infiltration. The mapping relationship between the ultimate bearing capacity and the initial rain intensity, the rain intensity variation coefficient, and the rainfall duration was established. With the analytic solution of the ultimate bearing capacity, the evolution characteristics of the bearing capacity for foundation were studied during the delayed-peak rainfall, and the effects of the initial rain intensity and the rain intensity coefficient on the ultimate bearing capacity for foundation were analyzed. The results show that during delayed-peak rainfall infiltration, the ultimate bearing capacity decreases gradually with a nonlinear velocity from low to high, which is different from the near linear reduction when encountering uniform rainfall. When the rain intensity coefficient is constant, ultimate bearing capacity for foundation decreases faster with the greater initial rain intensity. When the initial rain intensity is constant, the ultimate bearing capacity for foundation decreases faster with greater rain intensity variation coefficient.
To reveal the influence of delayed-peak rainfall infiltration on ultimate bearing capacity of an unsaturated foundation rapidly, the following research work was carried out. The Gardner’s permeability coefficient function and the soil-water characteristic curve model were introduced to simplify the Richards unsaturated seepage control equation, and the Laplace transform was adopted to derive the transient analytical solution of matrix suction for foundation under delayed-peak rainfall infiltration with rain intensity, which was verified with the finite element numerical simulation results. Based on the theory of shear strength for unsaturated soil and the transient analytical solution of matrix suction, the expression of transient ultimate bearing capacity for foundation was obtained under delayed-peak rainfall infiltration. The mapping relationship between the ultimate bearing capacity and the initial rain intensity, the rain intensity variation coefficient, and the rainfall duration was established. With the analytic solution of the ultimate bearing capacity, the evolution characteristics of the bearing capacity for foundation were studied during the delayed-peak rainfall, and the effects of the initial rain intensity and the rain intensity coefficient on the ultimate bearing capacity for foundation were analyzed. The results show that during delayed-peak rainfall infiltration, the ultimate bearing capacity decreases gradually with a nonlinear velocity from low to high, which is different from the near linear reduction when encountering uniform rainfall. When the rain intensity coefficient is constant, ultimate bearing capacity for foundation decreases faster with the greater initial rain intensity. When the initial rain intensity is constant, the ultimate bearing capacity for foundation decreases faster with greater rain intensity variation coefficient.
2023,43(2):39-43 DOI: 10.3880/j.issn.1006-7647.2023.02.006
Abstract:
Aiming at the problem that there is no standard test method for the shear strength of cement-based repair material and concrete interface, a double L direct shear test device was designed, which can effectively avoid the influence of bending stress and make pure shear failure at the interface. Based on this test device, the effects of concrete surface roughness, water content and interfacial agent type on the shear strength of mortar-concrete interface were studied. The results show that moderate roughness treatment is conducive to the improvement of shear strength, and the shear strength decreases when the roughness is too large. The higher the surface moisture content of concrete, the lower the interfacial shear strength will be, and the surface moisture content has a significant influence on the shear strength. The use of interfacial agent can strengthen the structure of interface transition zone, and the selection of appropriate interfacial agent according to the dry and wet conditions of concrete surface is helpful to improve the shear performance of the bonding interface.
Aiming at the problem that there is no standard test method for the shear strength of cement-based repair material and concrete interface, a double L direct shear test device was designed, which can effectively avoid the influence of bending stress and make pure shear failure at the interface. Based on this test device, the effects of concrete surface roughness, water content and interfacial agent type on the shear strength of mortar-concrete interface were studied. The results show that moderate roughness treatment is conducive to the improvement of shear strength, and the shear strength decreases when the roughness is too large. The higher the surface moisture content of concrete, the lower the interfacial shear strength will be, and the surface moisture content has a significant influence on the shear strength. The use of interfacial agent can strengthen the structure of interface transition zone, and the selection of appropriate interfacial agent according to the dry and wet conditions of concrete surface is helpful to improve the shear performance of the bonding interface.
FENG Yaxin, JIANG Zhaoqiang, SUN Yiqing, WANG Runying, SHEN Zhenzhong, XU Liqun, GAN Lei, LI Haoxuan, LIU Yuan, GUI Jingpeng
2023,43(2):44-50, 81 DOI: 10.3880/j.issn.1006-7647.2023.02.007
Abstract:
In order to study the influence of Duncan-Chang E-B model parameters and their interactions on dam deformation, the global sensitivity of parameters in Duncan-Chang E-B model was studied using the improved response surface method for a homogeneous loess dam. Firstly, five parameters including R f, γ, φ 0, K b and K , which have significant influence on the deformation of earth dam were screened out by fractional factorial design. Then the central composite design in the response surface method was used to conduct further global response surface analysis on the screening results and investigate the influence of parameters and their interaction on the deformation of earth dams. The results show that R f, γ and φ 0 are the three most sensitive parameters to dam displacement, and the interaction between them is also significantly sensitive to dam deformation, which is greater than the sensitivity of a single factor. Therefore, the interaction between the parameters should be considered in similar engineering calculations.
In order to study the influence of Duncan-Chang E-B model parameters and their interactions on dam deformation, the global sensitivity of parameters in Duncan-Chang E-B model was studied using the improved response surface method for a homogeneous loess dam. Firstly, five parameters including R f, γ, φ 0, K b and K , which have significant influence on the deformation of earth dam were screened out by fractional factorial design. Then the central composite design in the response surface method was used to conduct further global response surface analysis on the screening results and investigate the influence of parameters and their interaction on the deformation of earth dams. The results show that R f, γ and φ 0 are the three most sensitive parameters to dam displacement, and the interaction between them is also significantly sensitive to dam deformation, which is greater than the sensitivity of a single factor. Therefore, the interaction between the parameters should be considered in similar engineering calculations.
2023,43(2):51-57 DOI: 10.3880/j.issn.1006-7647.2023.02.008
Abstract:
Based on the economic design index of single 5% cement, the triaxial test of improved aeolian sand static in mixed cement silt was carried out.The stress-strain and strength characteristics of improved aeolian sand sample under different confining pressures were analyzed, based on which the change law of the viscosity and internal friction angle of different doping ratios, the failure form of improved aeolian sand, and the shear failure mechanism were revealed. The main results show the stress-strain relationship curves of improved aeolian sand are all strain softening curves.The elastic modulus and failure intensity are positively correlated with confining pressure, and elastic modulus reaches to its peak value when the amount of silt mixing is increased to 15%.The value of failure intensity is positively correlated with the amount of silt.The cohesion of modified aeolian sand is the largest under 10% silt mixture, and the internal friction angle increases monotonously with silt mixing amount. The reason is that cement hydrate is wrapped in the surface of sand particles, increasing the surface roughness and forming a network structure in the gap between sand particles.The sand particles are linked together and the relative movement of sand grains is hindered.Incorporating an appropriate amount of silt can fill the gaps between sand particles and hydrates, but excessive silt will restrict the hydration reaction, and at the same time, alkaline ions and hydrates react to produce sodium silicate and sodium aluminate with poor cementing capacity, resulting in a decrease in the overall performance of improved aeolian sand.
Based on the economic design index of single 5% cement, the triaxial test of improved aeolian sand static in mixed cement silt was carried out.The stress-strain and strength characteristics of improved aeolian sand sample under different confining pressures were analyzed, based on which the change law of the viscosity and internal friction angle of different doping ratios, the failure form of improved aeolian sand, and the shear failure mechanism were revealed. The main results show the stress-strain relationship curves of improved aeolian sand are all strain softening curves.The elastic modulus and failure intensity are positively correlated with confining pressure, and elastic modulus reaches to its peak value when the amount of silt mixing is increased to 15%.The value of failure intensity is positively correlated with the amount of silt.The cohesion of modified aeolian sand is the largest under 10% silt mixture, and the internal friction angle increases monotonously with silt mixing amount. The reason is that cement hydrate is wrapped in the surface of sand particles, increasing the surface roughness and forming a network structure in the gap between sand particles.The sand particles are linked together and the relative movement of sand grains is hindered.Incorporating an appropriate amount of silt can fill the gaps between sand particles and hydrates, but excessive silt will restrict the hydration reaction, and at the same time, alkaline ions and hydrates react to produce sodium silicate and sodium aluminate with poor cementing capacity, resulting in a decrease in the overall performance of improved aeolian sand.
2023,43(2):58-62, 88 DOI: 10.3880/j.issn.1006-7647.2023.02.009
Abstract:
Taking the rural Fushanchang village around a drinking headwater reservoir in western Hubei montane as a research example, an investigation was carried out on the current situation of rural domestic sewage discharge and treatment in western Hubei montane through on-site investigation and water quality testing.The results show that rural wastewater in western Hubei montane is mainly treated by three methods, including centralized micro-powered station, small micro-powered facility for three-household combined discharge, and three-format fermenting tanks.After treatment, the sewage is discharged into surface ditches, weirs and ponds or infiltrated into the ground. The test results of the effluent water quality of the three wastewater treatment methods cannot meet the requirements of rural domestic wastewater discharge water quality, and it has a certain impact on the water quality of the adjacent water source reservoir.The micro-powered sewage treatment facilities have high operating costs, complex operation and maintenance procedures, negligent management and short effective operation time, making it difficult to achieve the appropriate sewage treatment effect.Therefore, the study of new rural domestic wastewater treatment methods based on the characteristics of rural terrain and domestic wastewater discharge in western Hubei montane is imperative to ensure the safety and quality of the rural water environment.
Taking the rural Fushanchang village around a drinking headwater reservoir in western Hubei montane as a research example, an investigation was carried out on the current situation of rural domestic sewage discharge and treatment in western Hubei montane through on-site investigation and water quality testing.The results show that rural wastewater in western Hubei montane is mainly treated by three methods, including centralized micro-powered station, small micro-powered facility for three-household combined discharge, and three-format fermenting tanks.After treatment, the sewage is discharged into surface ditches, weirs and ponds or infiltrated into the ground. The test results of the effluent water quality of the three wastewater treatment methods cannot meet the requirements of rural domestic wastewater discharge water quality, and it has a certain impact on the water quality of the adjacent water source reservoir.The micro-powered sewage treatment facilities have high operating costs, complex operation and maintenance procedures, negligent management and short effective operation time, making it difficult to achieve the appropriate sewage treatment effect.Therefore, the study of new rural domestic wastewater treatment methods based on the characteristics of rural terrain and domestic wastewater discharge in western Hubei montane is imperative to ensure the safety and quality of the rural water environment.
2023,43(2):63-69, 75 DOI: 10.3880/j.issn.1006-7647.2023.02.010
Abstract:
In order to accurately detect the location and range of dam leakage channels and reduce the influence of the limitation and uncertainty of single method on the detection result, a method of combining high-density electrical method and comprehensive tracer method to detect the hidden dangers of dam leakage is proposed. The verification of a pumped storage power station example shows that, the results of the high-density electrical method can be verified by the comprehensive tracer method through several tracing tests. The dam leakage channel detection technology combined with high-density electrical method and comprehensive tracer method accurately reveals the location and range of the hidden danger of dam leakage, overcomes the non-unique defect of single method detection result. The combination of high-density electrical method and comprehensive tracer method for dam leakage channel detection has high efficiency and accuracy.
In order to accurately detect the location and range of dam leakage channels and reduce the influence of the limitation and uncertainty of single method on the detection result, a method of combining high-density electrical method and comprehensive tracer method to detect the hidden dangers of dam leakage is proposed. The verification of a pumped storage power station example shows that, the results of the high-density electrical method can be verified by the comprehensive tracer method through several tracing tests. The dam leakage channel detection technology combined with high-density electrical method and comprehensive tracer method accurately reveals the location and range of the hidden danger of dam leakage, overcomes the non-unique defect of single method detection result. The combination of high-density electrical method and comprehensive tracer method for dam leakage channel detection has high efficiency and accuracy.
2023,43(2):70-75 DOI: 10.3880/j.issn.1006-7647.2023.02.011
Abstract:
In hydrogeological survey, the situation of multiple aquifers is often encountered in borehole testing, and it is necessary to use packer system to isolate and detect each aquifer. Due to the inconvenience for field operation and high drilling conditions required, a multi-aquifer seepage tracing model without packer system was proposed. Considering different conditions of aquifer inflow and out flow without using plugging system, an electric conductivity tracer model for a multi-aquifer seepage system was established to determine the permeability parameters by measuring the conductivity of each aquifer during pumping. When only the outflow aquifer exists, the flow rate can be calculated directly by using the proportion relation between the area of conductivity curve and solute mass. When both outflow layer and inflow layer appear in borehole, the position of inflow layer can be found accurately according to the slope of electrical conductivity curve, and then the flow rate of aquifers can be calculated by the change of slope. In a field test, the hydrogeological parameters such as permeability coefficient, hydrostatic head, seepage velocity and water conductivity coefficient of each aquifer were calculated by using three methods. The results show that the detection results obtained by the conductivity tracing model is in good agreement with the isotope tracer test and water injection test, and the proposed model is simpler to operate, which can greatly improve the detection efficiency of aquifer hydrogeological parameters.
In hydrogeological survey, the situation of multiple aquifers is often encountered in borehole testing, and it is necessary to use packer system to isolate and detect each aquifer. Due to the inconvenience for field operation and high drilling conditions required, a multi-aquifer seepage tracing model without packer system was proposed. Considering different conditions of aquifer inflow and out flow without using plugging system, an electric conductivity tracer model for a multi-aquifer seepage system was established to determine the permeability parameters by measuring the conductivity of each aquifer during pumping. When only the outflow aquifer exists, the flow rate can be calculated directly by using the proportion relation between the area of conductivity curve and solute mass. When both outflow layer and inflow layer appear in borehole, the position of inflow layer can be found accurately according to the slope of electrical conductivity curve, and then the flow rate of aquifers can be calculated by the change of slope. In a field test, the hydrogeological parameters such as permeability coefficient, hydrostatic head, seepage velocity and water conductivity coefficient of each aquifer were calculated by using three methods. The results show that the detection results obtained by the conductivity tracing model is in good agreement with the isotope tracer test and water injection test, and the proposed model is simpler to operate, which can greatly improve the detection efficiency of aquifer hydrogeological parameters.
2023,43(2):76-81 DOI: 10.3880/j.issn.1006-7647.2023.02.012
Abstract:
To quickly and accurately predict the temperature history during the concrete construction period, a prediction model based on the long short-term memory (LSTM) network algorithm was proposed combined with the principal component analysis (PCA).Taking the baseboard of the Siyaogang Sluice and Bayaogang Sluice in Shanghai Chongming Island as an example, the PCA method was used to reduce the number of the possible influencing factors of the concrete temperature field, and then the LSTM prediction model of temperature history based on the temperature data of the Siyaogang Sluice baseboard was established to train the input principal components. Then the trained model was used for the fitting and prediction of the temperature history of the Bayaogang Sluice and was compared with the measured results. The results show that the predicted value fits well with the measured one with the RSM error within 2℃ and the coefficient of determination close to 1, meeting the requirements of engineering accuracy. The proposed method can partially be an alternative for FEM back-analysis, which can increase the efficiency for concrete temperature field prediction of pump and sluice projects.
To quickly and accurately predict the temperature history during the concrete construction period, a prediction model based on the long short-term memory (LSTM) network algorithm was proposed combined with the principal component analysis (PCA).Taking the baseboard of the Siyaogang Sluice and Bayaogang Sluice in Shanghai Chongming Island as an example, the PCA method was used to reduce the number of the possible influencing factors of the concrete temperature field, and then the LSTM prediction model of temperature history based on the temperature data of the Siyaogang Sluice baseboard was established to train the input principal components. Then the trained model was used for the fitting and prediction of the temperature history of the Bayaogang Sluice and was compared with the measured results. The results show that the predicted value fits well with the measured one with the RSM error within 2℃ and the coefficient of determination close to 1, meeting the requirements of engineering accuracy. The proposed method can partially be an alternative for FEM back-analysis, which can increase the efficiency for concrete temperature field prediction of pump and sluice projects.
2023,43(2):82-88 DOI: 10.3880/j.issn.1006-7647.2023.02.013
Abstract:
Aiming at the uncertainty in the results of the scheming optimization process influenced by subjective factors and the problem of optimal scheme selection during asphalt concrete mix designing, taking the mix design of the Qiaolabula asphalt concrete core wall project as an example, the projection pursuit regression(PPR) modelling technique combined with the TOPSIS comprehensive evaluation method based on entropy weights (PPR-TOPSIS analysis method) was proposed for the comprehensive benefits of the mix evaluation indexes. The results show that the established PPR model for asphalt concrete evaluation indexes is highly accurate in calculation, with a pass rate of 93.1% and an average relative error of 2.01%, which can accurately predict the evaluation indexes of the mix ratio schemes with different combinations of factor levels. The test results of the best mix ratio scheme analyzed by the PPR-TOPSIS comprehensive evaluation method can satisfy the specification criteria. Compared with the traditional design method, the influence of human subjective factors can be reduced and the solution search and quantitative evaluation of the combination of all test factors can be realized by the proposed method, and the obtained ratio solution is more reasonable.
Aiming at the uncertainty in the results of the scheming optimization process influenced by subjective factors and the problem of optimal scheme selection during asphalt concrete mix designing, taking the mix design of the Qiaolabula asphalt concrete core wall project as an example, the projection pursuit regression(PPR) modelling technique combined with the TOPSIS comprehensive evaluation method based on entropy weights (PPR-TOPSIS analysis method) was proposed for the comprehensive benefits of the mix evaluation indexes. The results show that the established PPR model for asphalt concrete evaluation indexes is highly accurate in calculation, with a pass rate of 93.1% and an average relative error of 2.01%, which can accurately predict the evaluation indexes of the mix ratio schemes with different combinations of factor levels. The test results of the best mix ratio scheme analyzed by the PPR-TOPSIS comprehensive evaluation method can satisfy the specification criteria. Compared with the traditional design method, the influence of human subjective factors can be reduced and the solution search and quantitative evaluation of the combination of all test factors can be realized by the proposed method, and the obtained ratio solution is more reasonable.
2023,43(2):89-95 DOI: 10.3880/j.issn.1006-7647.2023.02.014
Abstract:
Surface cracks in the impervious concrete panel of a concrete faced rockfill dam were examined by employing several non-destructive testing methods, including ground penetrating radar, impact echo and ultrasonic plane inspection. The characteristics of electromagnetic response of different types of cracks were analyzed, the effects and influencing factors of impact echo and ultrasonic plane measurement upon different cracks were assessed with error analysis. By comparing with direct drilling results, the effectiveness and accuracy of integrated non-destructive method, which was established by incorporating holistic rapid inspecting and local accurate measurement, were discussed in crack detection. The results indicate that ground penetrating radar, with its intuitive and high efficiency, can achieve an overall investigation of impervious panel cracks, and quickly indentify their distribution and physical properties. The impact echo and ultrasonic plane mearsuring method, with their accuracy and flexibility, can further determine the crack depth. Through reasonably combining testing methods and scientifically laying out survey lines, the proposed methods can identify the distribution, basic properties, scope and size of cracks, whilst improving the comprehensiveness, accuracy and precision of detection.
Surface cracks in the impervious concrete panel of a concrete faced rockfill dam were examined by employing several non-destructive testing methods, including ground penetrating radar, impact echo and ultrasonic plane inspection. The characteristics of electromagnetic response of different types of cracks were analyzed, the effects and influencing factors of impact echo and ultrasonic plane measurement upon different cracks were assessed with error analysis. By comparing with direct drilling results, the effectiveness and accuracy of integrated non-destructive method, which was established by incorporating holistic rapid inspecting and local accurate measurement, were discussed in crack detection. The results indicate that ground penetrating radar, with its intuitive and high efficiency, can achieve an overall investigation of impervious panel cracks, and quickly indentify their distribution and physical properties. The impact echo and ultrasonic plane mearsuring method, with their accuracy and flexibility, can further determine the crack depth. Through reasonably combining testing methods and scientifically laying out survey lines, the proposed methods can identify the distribution, basic properties, scope and size of cracks, whilst improving the comprehensiveness, accuracy and precision of detection.
2023,43(2):96-101 DOI: 10.3880/j.issn.1006-7647.2023.02.015
Abstract:
In order to deeply mine the dynamic correlation between the front and back information in the time series data,explore the internal influence mechanism of dam deformation, and effectively improve the prediction accuracy of the model, a bidirectional gated recurrent unit (BiGRU) prediction model based on mixed attention mechanism and whale optimization algorithm (WOA) was constructed. WOA was used to optimize the hyperparameters of BiGRU to effectively mine the deep information of deformation data in the time dimension.A mixed attention mechanism that combines factor attention mechanism (FATT) and temporal attention mechanism (TATT) was introduced to calculate the contribution rate of each impact factor, so as to visualize the model and improve the ability to capture the dynamic changes of environmental factors. Taking a high arch dam as an example, the prediction results of this model were compared with those of various commonly used models. The results show that the prediction accuracy of this model is significantly improved, and the calculation of contribution rate is in line with the research results of dam deformation, which verifies the superiority and rationality of the model in dam deformation prediction.
In order to deeply mine the dynamic correlation between the front and back information in the time series data,explore the internal influence mechanism of dam deformation, and effectively improve the prediction accuracy of the model, a bidirectional gated recurrent unit (BiGRU) prediction model based on mixed attention mechanism and whale optimization algorithm (WOA) was constructed. WOA was used to optimize the hyperparameters of BiGRU to effectively mine the deep information of deformation data in the time dimension.A mixed attention mechanism that combines factor attention mechanism (FATT) and temporal attention mechanism (TATT) was introduced to calculate the contribution rate of each impact factor, so as to visualize the model and improve the ability to capture the dynamic changes of environmental factors. Taking a high arch dam as an example, the prediction results of this model were compared with those of various commonly used models. The results show that the prediction accuracy of this model is significantly improved, and the calculation of contribution rate is in line with the research results of dam deformation, which verifies the superiority and rationality of the model in dam deformation prediction.
2023,43(2):102-108 DOI: 10.3880/j.issn.1006-7647.2023.02.016
Abstract:
To solve the problem that the internal correlation between multiple measuring points cannot be considered by traditional single measuring point monitoring models, which is difficult to reflect the regional characteristics of high arch dam deformation in space. A high arch dam deformation prediction model based on clustering partition and a multi-output least square support vector regression machine (MO-LSSVR) algorithm is proposed. Based on the composite similarity index between the measuring points, the clustering partition of spatial correlation measuring points is realized by hierarchical agglomerative clustering (HAC) algorithm. The MO-LSSVR algorithm integrating the correlation characteristics of measuring points is then used to model the points in the partition. The engineering example results show that the clustering partition results are consistent with the spatial distribution characteristics of dam deformation. The MO-LSSVR model based on the reasonable partition results has high accuracy and robustness, which provides a new method to accurately predict the dam deformation and monitoring the overall safety state of the dam from the multi-measuring points correlation dimension.
To solve the problem that the internal correlation between multiple measuring points cannot be considered by traditional single measuring point monitoring models, which is difficult to reflect the regional characteristics of high arch dam deformation in space. A high arch dam deformation prediction model based on clustering partition and a multi-output least square support vector regression machine (MO-LSSVR) algorithm is proposed. Based on the composite similarity index between the measuring points, the clustering partition of spatial correlation measuring points is realized by hierarchical agglomerative clustering (HAC) algorithm. The MO-LSSVR algorithm integrating the correlation characteristics of measuring points is then used to model the points in the partition. The engineering example results show that the clustering partition results are consistent with the spatial distribution characteristics of dam deformation. The MO-LSSVR model based on the reasonable partition results has high accuracy and robustness, which provides a new method to accurately predict the dam deformation and monitoring the overall safety state of the dam from the multi-measuring points correlation dimension.
2023,43(2):109-114 DOI: 10.3880/j.issn.1006-7647.2023.02.017
Abstract:
Aiming at the problem of gross errors and abnormal measurements in the deformation monitoring data of concrete dams, a data anomaly identification and reconstruction model is proposed. The association rules are used to quantify the correlation between deformation sequences and water level sequences, and the monitoring data are input into the DBSCAN clustering algorithm to find the abnormal points.The association results are used to classify the data abnormal points into two categories, coarse error points and points reflecting the dam morphology.The points reflecting the dam morphology are retained and the coarse error points are eliminated, and modified wavelet neural network is used to reconstruct the coarse difference data to ensure the integrity of the monitoring sequence. The application results of an arch dam deformation monitoring data show that the model can accurately identify the abnormal values in the monitoring data and can obtain more accurate reconstructed data, providing a new analysis method for the evaluation of measured properties of a dam.
Aiming at the problem of gross errors and abnormal measurements in the deformation monitoring data of concrete dams, a data anomaly identification and reconstruction model is proposed. The association rules are used to quantify the correlation between deformation sequences and water level sequences, and the monitoring data are input into the DBSCAN clustering algorithm to find the abnormal points.The association results are used to classify the data abnormal points into two categories, coarse error points and points reflecting the dam morphology.The points reflecting the dam morphology are retained and the coarse error points are eliminated, and modified wavelet neural network is used to reconstruct the coarse difference data to ensure the integrity of the monitoring sequence. The application results of an arch dam deformation monitoring data show that the model can accurately identify the abnormal values in the monitoring data and can obtain more accurate reconstructed data, providing a new analysis method for the evaluation of measured properties of a dam.
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2019,39(1):1-6, DOI: 10.3880/j.issn.1006-7647.2019.01.001
Abstract:
Since flood is formed by storm, flood forecasting is the continuity of precipitation prediction. In recent 30 years, numerical weather prediction has made great advance, but the attempt to apply watershed hydrological model in flood forecasting is slow. The reasons for the different accuracies between numerical weather prediction and flood forecasting are investigated. Successful experience of numerical weather prediction and the problems of watershed hydrological model in the application of flood forecasting are discussed by means of comparison of the weather model and the watershed hydrological model. Problems discussed are the prediction methods and the forecasting time, the initial fields and the boundary value fields, data assimilation and data fusion. It is expected that great inspirations to flood forecasting can be obtained from the successful experience of numerical weather prediction. In the near future, seamless connection can be realized between weather prediction and flood forecasting, and as a result, the accuracy of flood forecasting can thus be improved and the forecasting time can be extended.
Since flood is formed by storm, flood forecasting is the continuity of precipitation prediction. In recent 30 years, numerical weather prediction has made great advance, but the attempt to apply watershed hydrological model in flood forecasting is slow. The reasons for the different accuracies between numerical weather prediction and flood forecasting are investigated. Successful experience of numerical weather prediction and the problems of watershed hydrological model in the application of flood forecasting are discussed by means of comparison of the weather model and the watershed hydrological model. Problems discussed are the prediction methods and the forecasting time, the initial fields and the boundary value fields, data assimilation and data fusion. It is expected that great inspirations to flood forecasting can be obtained from the successful experience of numerical weather prediction. In the near future, seamless connection can be realized between weather prediction and flood forecasting, and as a result, the accuracy of flood forecasting can thus be improved and the forecasting time can be extended.
2020,40(1):1-9, DOI: 10.3880/j.issn.1006-7647.2020.01.001
Abstract:
In order to reasonably synthesize the carrying capacity of regional water resources by the four elements of water quantity, water quality, water space and stream flow, a water resources carrying capacity evaluation model based on the four elements and a risk matrix(QQSS-RM)was proposed. Firstly, 48 preliminary evaluation indicators under the subsystem of quantity-quality-space-stream were constructed and the weight of each evaluation index in the four elements was calculated by expert consultation information method and genetic analytic hierarchy process. Through screening and analysis, 8 comprehensive evaluation indexes were obtained to construct the evaluation index system for the regional water resources carrying capacity. Secondly, 4 evaluation grade criteria of 8 comprehensive evaluation indexes were obtained by referring to relevant literature and expert opinions. Finally, an evaluation model of water resources carrying capacity based on QQSS-RM was constructed, which was applied to three third grade zones of water resources in the Xiliao River Basin. The results show that the water resources carrying capacity evaluation level of Xilamulun River and Laoha River, Wulijimulun River and the downstream of Xiliao River are overloaded, critical overloaded and overloaded respectively, showing a poor water resources carrying capacity of the Xiliao River Basin. The evaluation results are basically consistent with the current status of the Xiliao River Basin, indicating that the QQSS-RM model has better application value in regional water resources carrying capacity evaluation.
In order to reasonably synthesize the carrying capacity of regional water resources by the four elements of water quantity, water quality, water space and stream flow, a water resources carrying capacity evaluation model based on the four elements and a risk matrix(QQSS-RM)was proposed. Firstly, 48 preliminary evaluation indicators under the subsystem of quantity-quality-space-stream were constructed and the weight of each evaluation index in the four elements was calculated by expert consultation information method and genetic analytic hierarchy process. Through screening and analysis, 8 comprehensive evaluation indexes were obtained to construct the evaluation index system for the regional water resources carrying capacity. Secondly, 4 evaluation grade criteria of 8 comprehensive evaluation indexes were obtained by referring to relevant literature and expert opinions. Finally, an evaluation model of water resources carrying capacity based on QQSS-RM was constructed, which was applied to three third grade zones of water resources in the Xiliao River Basin. The results show that the water resources carrying capacity evaluation level of Xilamulun River and Laoha River, Wulijimulun River and the downstream of Xiliao River are overloaded, critical overloaded and overloaded respectively, showing a poor water resources carrying capacity of the Xiliao River Basin. The evaluation results are basically consistent with the current status of the Xiliao River Basin, indicating that the QQSS-RM model has better application value in regional water resources carrying capacity evaluation.
2020,40(2):1-5, DOI: 10.3880/j.issn.1006-7647.2020.02.001
Abstract:
Problems exist in the construction and management of ecological irrigation districts, such as low efficiency in industry and resources, irrigation water deterioration and decreased ecological diversity. Based on the theoretical guidance of the rural revitalization strategy and its 20 words general requirements, construction and management of ecological irrigation districts under the guidance of the rural revitalization strategy were discussed. Three red lines for the construction and management of irrigation districts were proposed, including the baseline of agricultural quality and production, the baseline of ecological environment and the upper limit of resources development and utilization. The ecological irrigation districts should develop in the direction of effective supply of food production and other products, perfection in ecological environmental landscape, protection and high-efficiency utilization of resources. This paper provides scientific references of sustainable and green development for ecological irrigation districts.
Problems exist in the construction and management of ecological irrigation districts, such as low efficiency in industry and resources, irrigation water deterioration and decreased ecological diversity. Based on the theoretical guidance of the rural revitalization strategy and its 20 words general requirements, construction and management of ecological irrigation districts under the guidance of the rural revitalization strategy were discussed. Three red lines for the construction and management of irrigation districts were proposed, including the baseline of agricultural quality and production, the baseline of ecological environment and the upper limit of resources development and utilization. The ecological irrigation districts should develop in the direction of effective supply of food production and other products, perfection in ecological environmental landscape, protection and high-efficiency utilization of resources. This paper provides scientific references of sustainable and green development for ecological irrigation districts.
2020,40(3):1-7, DOI: 10.3880/j.issn.1006-7647.2020.03.001
Abstract:
Spring ecological water requirement for the fishes in the Yellow River Estuary should meet the needs of the habitat and spawning ground of freshwater fishes, channel of migratory fishes, and spawning ground of offshore migratory fishes. According to the living habit of fishes, the time of runoff propagation, the mixing time of fresh water and salt water, and the discharge feature since the operation of the Xiaolangdi Reservoir, key attention should be paid to the water requirement from March to May. A minimum ecological flow discharge of 240 m3/s is needed according to the living habit of fishes and the continuity of the migration channel. A flow discharge pulse with a peak of 890 m3/s, lasting for 8d in the middle stage of April is also needed considering the pulse characteristics in nature period. In this condition, the runoff in spring is 21. 6×108 m3, satisfying the requirement of 21×108 m3 for the low salt spawning condition of offshore migratory fishes. The mean annual spring runoff is 21×108 m3 since the operation of the Xiaolangdi Reservoir. It is of great feasibility to satisfy the fish ecological water requirement by optimizing the annual or the interannual operation modes.
Spring ecological water requirement for the fishes in the Yellow River Estuary should meet the needs of the habitat and spawning ground of freshwater fishes, channel of migratory fishes, and spawning ground of offshore migratory fishes. According to the living habit of fishes, the time of runoff propagation, the mixing time of fresh water and salt water, and the discharge feature since the operation of the Xiaolangdi Reservoir, key attention should be paid to the water requirement from March to May. A minimum ecological flow discharge of 240 m3/s is needed according to the living habit of fishes and the continuity of the migration channel. A flow discharge pulse with a peak of 890 m3/s, lasting for 8d in the middle stage of April is also needed considering the pulse characteristics in nature period. In this condition, the runoff in spring is 21. 6×108 m3, satisfying the requirement of 21×108 m3 for the low salt spawning condition of offshore migratory fishes. The mean annual spring runoff is 21×108 m3 since the operation of the Xiaolangdi Reservoir. It is of great feasibility to satisfy the fish ecological water requirement by optimizing the annual or the interannual operation modes.
2015,35(4):1-5, DOI: 10.3880/j.issn.1006-7647.2015.04.001
Abstract:
Through the analysis of parameters and structure, it was found that the description of storm water management model(SWMM) on the process of rainfall-runoff formation in urban areas is consistent with urban runoff yield and concentration rule. The physical concept of SWMM is clear because the runoff yield analytical methods are based on hydrology, and concentration analytical methods are based on hydraulics. The parameters of SWMM almost have geometric or physical meanings, but there are some complementary(or dependency) relationships among some parameters. Therefore, it is necessary to reduce the influence of the equifinality for different parameters on parameter calibration. The composition of the process of rainfall-runoff formation in catchment area exit using the method of simultaneous summation shows that the interference between stormflows from different areas is neglected.
Through the analysis of parameters and structure, it was found that the description of storm water management model(SWMM) on the process of rainfall-runoff formation in urban areas is consistent with urban runoff yield and concentration rule. The physical concept of SWMM is clear because the runoff yield analytical methods are based on hydrology, and concentration analytical methods are based on hydraulics. The parameters of SWMM almost have geometric or physical meanings, but there are some complementary(or dependency) relationships among some parameters. Therefore, it is necessary to reduce the influence of the equifinality for different parameters on parameter calibration. The composition of the process of rainfall-runoff formation in catchment area exit using the method of simultaneous summation shows that the interference between stormflows from different areas is neglected.
2019,39(3):18-23, DOI: 10.3880/j.issn.1006-7647.2019.03.004
Abstract:
In order to comprehensively understand the current status of global hydropower development, to analyze the development potential of hydropower markets in various countries, and to guide hydropower enterprises to explore the international market, the world is divided into six regions, including North America, South America, Africa, Europe, Central and South Asia, East Asia and the Pacific Rim. The current status of hydropower development in various regions of the world, as well as the corresponding status and development goals in key countries are elaborated. Based on the water resources and the development situation, the exploring potential of the global hydropower market is analyzed. The results show that the total installed capacity of hydropower in the world continues to increase but the annual increment shows a downward trend. The hydropower development potential in Africa, South Asia and Southeast Asia is relatively large. In terms of technology development, the countries such as Indonesia, Peru, DR Congo, Tajikistan, Nepal, Angola, Myanmar and Bolivia, etc. , have broad prospects for future hydropower markets.
In order to comprehensively understand the current status of global hydropower development, to analyze the development potential of hydropower markets in various countries, and to guide hydropower enterprises to explore the international market, the world is divided into six regions, including North America, South America, Africa, Europe, Central and South Asia, East Asia and the Pacific Rim. The current status of hydropower development in various regions of the world, as well as the corresponding status and development goals in key countries are elaborated. Based on the water resources and the development situation, the exploring potential of the global hydropower market is analyzed. The results show that the total installed capacity of hydropower in the world continues to increase but the annual increment shows a downward trend. The hydropower development potential in Africa, South Asia and Southeast Asia is relatively large. In terms of technology development, the countries such as Indonesia, Peru, DR Congo, Tajikistan, Nepal, Angola, Myanmar and Bolivia, etc. , have broad prospects for future hydropower markets.
2019,39(4):1-6, DOI: 10.3880/j.issn.1006-7647.2019.04.001
Abstract:
To examine the damage causes of warping dams and their impacts on sediment delivery into the Yellow River, the characteristics of the rainstorm process at August 17 and the inflow of water-sediment into the Yellow River were obtained based on the field investigation results of 19 warping dam breaches and the data of hydrological stations and rainfall stations in Xiliugou and Hantaichuan watersheds. According to the structure and operation characteristics of the warping dams, combined with the detailed investigation of the flood-induced damage situation, especially the erosion form at the break sites, the causes of flood-induced damage were analyzed from the aspects of rainfall, planning, design, construction and operation management of the warping dams. The break modes and sand-blocking effects of the warping dams were qualitatively presented. Suggestions are proposed, including optimizing dam-system layout and construction standard, improving the structure of drainage structures, strengthening construction quality management, and paying attention to non-engineering measures such as early warning and prediction.
To examine the damage causes of warping dams and their impacts on sediment delivery into the Yellow River, the characteristics of the rainstorm process at August 17 and the inflow of water-sediment into the Yellow River were obtained based on the field investigation results of 19 warping dam breaches and the data of hydrological stations and rainfall stations in Xiliugou and Hantaichuan watersheds. According to the structure and operation characteristics of the warping dams, combined with the detailed investigation of the flood-induced damage situation, especially the erosion form at the break sites, the causes of flood-induced damage were analyzed from the aspects of rainfall, planning, design, construction and operation management of the warping dams. The break modes and sand-blocking effects of the warping dams were qualitatively presented. Suggestions are proposed, including optimizing dam-system layout and construction standard, improving the structure of drainage structures, strengthening construction quality management, and paying attention to non-engineering measures such as early warning and prediction.
2019,39(2):1-6, DOI: 10.3880/j.issn.1006-7647.2019.02.001
Abstract:
To cope with the new challenges of environmental flow research under hydrology, climate and ecosystem changes, research results from both China and abroad have been summarized. Five aspects of shortcomings in the current environmental flow research are pointed out, which also belong to frontier problems and challenges, including(1)Global environmental change and instability; (2)Dynamic simulation of eco-hydrological process in which the transition of hydrological regime from static evaluation to dynamic characteristic evaluation is the key; (3)Characteristics of eco-hydrological relationship in which the coupling research of ecosystem state, process variables and species characteristics, and the research of ecological characteristics, spatial and temporal scales of environmental flows are the key points; (4)Key indicators in environmental flow evaluation; (5)Ecology extension of environmental flow forecasting. To solve these problems, research directions of environmental flows in the background of the Anthropocene are proposed. Dynamic adaptive management of ecological objectives and basic research of ecology from local to reginal areas should be strengthened. Mechanisms of eco-hydrological response based on process should be completed and phased implementation of non-hydrological indicator coupling should be intensified. Evaluation and application of environmental flows under adaptive management should be strengthened to guarantee ecological integrity.
To cope with the new challenges of environmental flow research under hydrology, climate and ecosystem changes, research results from both China and abroad have been summarized. Five aspects of shortcomings in the current environmental flow research are pointed out, which also belong to frontier problems and challenges, including(1)Global environmental change and instability; (2)Dynamic simulation of eco-hydrological process in which the transition of hydrological regime from static evaluation to dynamic characteristic evaluation is the key; (3)Characteristics of eco-hydrological relationship in which the coupling research of ecosystem state, process variables and species characteristics, and the research of ecological characteristics, spatial and temporal scales of environmental flows are the key points; (4)Key indicators in environmental flow evaluation; (5)Ecology extension of environmental flow forecasting. To solve these problems, research directions of environmental flows in the background of the Anthropocene are proposed. Dynamic adaptive management of ecological objectives and basic research of ecology from local to reginal areas should be strengthened. Mechanisms of eco-hydrological response based on process should be completed and phased implementation of non-hydrological indicator coupling should be intensified. Evaluation and application of environmental flows under adaptive management should be strengthened to guarantee ecological integrity.
2021,41(2):1-7, DOI: 10.3880/j.issn.1006-7647.2021.02.001
Abstract:
An improved corridor constraint and IPSO-DPSA algorithm were proposed to solve the problem of morphological distortion of the dispatching line in the reservoir operation optimization process. Based on the hybrid algorithm of particle swarm optimization and dynamic programming successive approximation, this method optimizes the evolution process by introducing improved corridor constraints, special individual evolution mode, external elite set strategy, making the solution set as close as possible to the Pareto-optimal front of the multi-objective problem. The case study of the multi-objective optimization problem of the scheduling graph of the Chitan Reservoir shows that the algorithm can effectively control the morphological distortion of the dispatching line in the optimization process, and has good optimization performance.
An improved corridor constraint and IPSO-DPSA algorithm were proposed to solve the problem of morphological distortion of the dispatching line in the reservoir operation optimization process. Based on the hybrid algorithm of particle swarm optimization and dynamic programming successive approximation, this method optimizes the evolution process by introducing improved corridor constraints, special individual evolution mode, external elite set strategy, making the solution set as close as possible to the Pareto-optimal front of the multi-objective problem. The case study of the multi-objective optimization problem of the scheduling graph of the Chitan Reservoir shows that the algorithm can effectively control the morphological distortion of the dispatching line in the optimization process, and has good optimization performance.
2020,40(1):17-24, DOI: 10.3880/j.issn.1006-7647.2020.01.003
Abstract:
The geological disaster chain related to landslide dams has caused a lot of economic losses and casualties to China every year. Based on data statistics, the triggering factors and distribution rules of landslide dams in China in the past 10 years were analyzed. The results show that, there has been more than 100 recorded landslide dams in China. Earthquakes and heavy rainfalls are the main trigger factors, since they account for more than 90% of the total statistics. In terms of geographical distribution, Southwestern China is the heavy disaster-area of hazards related to landslide dams, and the landslide dam number accounts for more than 80% of the total statistics. The number of landslide dams in Sichuan Province is far more than that of other provinces, as it has suffered from the Wenchuan earthquake and the Lushan earthquake. Taiwan Province ranks the second, since there are 11 landslide dams recorded in the past 10 years due to the impact of typhoons yearly, accounting for 10. 2% of the total, followed by Yunnan, Chongqing and other provinces. In terms of temporal distribution, the number of landslide dams is basically fluctuating within the normal range except for the year 2008.
The geological disaster chain related to landslide dams has caused a lot of economic losses and casualties to China every year. Based on data statistics, the triggering factors and distribution rules of landslide dams in China in the past 10 years were analyzed. The results show that, there has been more than 100 recorded landslide dams in China. Earthquakes and heavy rainfalls are the main trigger factors, since they account for more than 90% of the total statistics. In terms of geographical distribution, Southwestern China is the heavy disaster-area of hazards related to landslide dams, and the landslide dam number accounts for more than 80% of the total statistics. The number of landslide dams in Sichuan Province is far more than that of other provinces, as it has suffered from the Wenchuan earthquake and the Lushan earthquake. Taiwan Province ranks the second, since there are 11 landslide dams recorded in the past 10 years due to the impact of typhoons yearly, accounting for 10. 2% of the total, followed by Yunnan, Chongqing and other provinces. In terms of temporal distribution, the number of landslide dams is basically fluctuating within the normal range except for the year 2008.
2019,39(3):1-5, DOI: 10.3880/j.issn.1006-7647.2019.03.001
Abstract:
The reservoirs(Xiluodu, Xiangjiaba, Zipingpu, Pubugou, and Tingzikou)in the upper Yangtze River were considered as the object of study. A nonlinear safety degree strategy for the joint flood control system of the multi-reservoirs in the upper Yangtze River was proposed, based on which a flood storage capacity optimization distribution model for multi-reservoirs was constructed and an in-depth discussion for the flood control effect of the nonlinear safety degree strategy was conducted. The results show that compared with linear safety degree strategy of multi-reservoirs, the flood control capacity of Xiluodu reservoir can be less consumed by increasing the usage of the flood control capacity in other reservoirs by the nonlinear strategy in the condition that the flood control effect of the downstream is not deteriorated. The application of the nonlinear safety degree strategy can relatively balance the flood storage capacity allocation of the reservoirs, make the reservoirs share the flood risk of the flood control areas, give full play to the flood control benefits of the reservoirs, and ensure the stable and safe operation of the multi-reservoir system.
The reservoirs(Xiluodu, Xiangjiaba, Zipingpu, Pubugou, and Tingzikou)in the upper Yangtze River were considered as the object of study. A nonlinear safety degree strategy for the joint flood control system of the multi-reservoirs in the upper Yangtze River was proposed, based on which a flood storage capacity optimization distribution model for multi-reservoirs was constructed and an in-depth discussion for the flood control effect of the nonlinear safety degree strategy was conducted. The results show that compared with linear safety degree strategy of multi-reservoirs, the flood control capacity of Xiluodu reservoir can be less consumed by increasing the usage of the flood control capacity in other reservoirs by the nonlinear strategy in the condition that the flood control effect of the downstream is not deteriorated. The application of the nonlinear safety degree strategy can relatively balance the flood storage capacity allocation of the reservoirs, make the reservoirs share the flood risk of the flood control areas, give full play to the flood control benefits of the reservoirs, and ensure the stable and safe operation of the multi-reservoir system.
2017,37(4):1-7, DOI: 10.3880/j.issn.1006-7647.2017.04.001
Abstract:
The hydrological principle of the structure and parameters of watershed hydrological models, the physical coupling relationship between the structure and parameters, and the essential difference between lumped and distributed watershed hydrological models were investigated. The characteristics of the solution methods for these two models, and the reasons causing the phenomenon of equifinality for different parameters during the calibration of the watershed hydrological models, as well as methods to alleviate the effects of this phenomenon, are discussed. A method for verification and comparison of the watershed hydrological models is proposed.
The hydrological principle of the structure and parameters of watershed hydrological models, the physical coupling relationship between the structure and parameters, and the essential difference between lumped and distributed watershed hydrological models were investigated. The characteristics of the solution methods for these two models, and the reasons causing the phenomenon of equifinality for different parameters during the calibration of the watershed hydrological models, as well as methods to alleviate the effects of this phenomenon, are discussed. A method for verification and comparison of the watershed hydrological models is proposed.
2019,39(3):6-10, DOI: 10.3880/j.issn.1006-7647.2019.03.002
Abstract:
Aiming at the complex problems of water resources in Beijing-Tianjin-Hebei region, an overall regulation and control idea based on the theory of virtuous circulation of water resources is proposed, which includes the smooth circulation of natural water resources and the cooperative equilibrium of social water resources circulation. Coping strategies are put forward in five aspects, including nature-enriched water regulation, combination of concentrated and sporadic sewage treatment, unified regulation, water consumption management, and synergetic utilization of water market. The present study is aimed at achieving virtuous circulation to support sustainable utilization of water resources and green development.
Aiming at the complex problems of water resources in Beijing-Tianjin-Hebei region, an overall regulation and control idea based on the theory of virtuous circulation of water resources is proposed, which includes the smooth circulation of natural water resources and the cooperative equilibrium of social water resources circulation. Coping strategies are put forward in five aspects, including nature-enriched water regulation, combination of concentrated and sporadic sewage treatment, unified regulation, water consumption management, and synergetic utilization of water market. The present study is aimed at achieving virtuous circulation to support sustainable utilization of water resources and green development.
2019,39(1):7-14, DOI: 10.3880/j.issn.1006-7647.2019.01.002
Abstract:
The goal of water governance is specified from five dimensions, including resources, economy, sociality, ecology and environment. The evaluation index system of the water governance in China is systematically designed. The current situation of water governance is comprehensively evaluated and the variation trend of China's water governance in 2020-2050 is forecasted using the hierarchical equal weight method and the target consistency method. The results show that the index of water governance has been increased quickly from below 0. 235 to near 0. 70 since the reform and opening-up. The acceleration period of water governance is from 2010 to 2015, in which the water governance index has increased about 50%. It is expected that the water governance index will exceed 0. 85 by 2020, and the harmonization between economic development and water resources utilization will be realized. The index of water governance will reach 0. 95 by 2030, and the harmonization between economic development and water pollution will be realized. The capacity of water safety support can be significantly improved and the water governance targets can be realized basically. The index of water governance will reach the optimum value of 1 by 2050, and the water resources utilization, water pollution discharge, water disaster loss and water ecology degradation area will be zero growth, fully achieving the harmony between human and water.
The goal of water governance is specified from five dimensions, including resources, economy, sociality, ecology and environment. The evaluation index system of the water governance in China is systematically designed. The current situation of water governance is comprehensively evaluated and the variation trend of China's water governance in 2020-2050 is forecasted using the hierarchical equal weight method and the target consistency method. The results show that the index of water governance has been increased quickly from below 0. 235 to near 0. 70 since the reform and opening-up. The acceleration period of water governance is from 2010 to 2015, in which the water governance index has increased about 50%. It is expected that the water governance index will exceed 0. 85 by 2020, and the harmonization between economic development and water resources utilization will be realized. The index of water governance will reach 0. 95 by 2030, and the harmonization between economic development and water pollution will be realized. The capacity of water safety support can be significantly improved and the water governance targets can be realized basically. The index of water governance will reach the optimum value of 1 by 2050, and the water resources utilization, water pollution discharge, water disaster loss and water ecology degradation area will be zero growth, fully achieving the harmony between human and water.
2017,37(3):1-6, DOI: 10.3880/j.issn.1006-7647.2017.03.001
Abstract:
The development process of research on the water resources carrying capacity in China is systematically summarized, and it can be divided into five stages: the creation of conception, the preliminary study, the gradual improvement, the difficult development, and the innovation era. On the basis of comparison of research methods, the calculation methods of water resources carrying capacity can be divided into three categories: the empirical formula method, comprehensive evaluation method, and system analysis method. The control objective inversion model(COIM)based on simulation and optimization and its applications are introduced. It is pointed out that research on the water resources carrying capacity in the future focuses on: using the empirical formula method to calculate the national water resources carrying capacity and system analysis method for detailed calculation; constructing the calculation model of water resources carrying capacity and forewarning system platform; studying the dynamic carrying capacity of water resources under the changing environment; and considering the current achievements of water resources regulation and the balance development of water resources and economic society.
The development process of research on the water resources carrying capacity in China is systematically summarized, and it can be divided into five stages: the creation of conception, the preliminary study, the gradual improvement, the difficult development, and the innovation era. On the basis of comparison of research methods, the calculation methods of water resources carrying capacity can be divided into three categories: the empirical formula method, comprehensive evaluation method, and system analysis method. The control objective inversion model(COIM)based on simulation and optimization and its applications are introduced. It is pointed out that research on the water resources carrying capacity in the future focuses on: using the empirical formula method to calculate the national water resources carrying capacity and system analysis method for detailed calculation; constructing the calculation model of water resources carrying capacity and forewarning system platform; studying the dynamic carrying capacity of water resources under the changing environment; and considering the current achievements of water resources regulation and the balance development of water resources and economic society.
2016,36(3):1-4, DOI: 10.3880/j.issn.1006-7647.2016.03.001
Abstract:
The characteristics and advantages of the big data method are discussed in this paper. In the method, mathematical formulas are replaced by intensive data in order to precisely describe the temporal and spatial variation of hydrological phenomena or the solution of a differential equation. The reasons why hydrology needs big data and technical support for obtaining hydrological big data are also discussed. The big data method may inspire the innovation of scientific thinking and become a way of solving complex problems in hydrology.
The characteristics and advantages of the big data method are discussed in this paper. In the method, mathematical formulas are replaced by intensive data in order to precisely describe the temporal and spatial variation of hydrological phenomena or the solution of a differential equation. The reasons why hydrology needs big data and technical support for obtaining hydrological big data are also discussed. The big data method may inspire the innovation of scientific thinking and become a way of solving complex problems in hydrology.
2017,37(5):1-8, DOI: 10.3880/j.issn.1006-7647.2017.05.001
Abstract:
In order to simulate the aqueduct damage and evaluate the structure safety in a reasonable way, aqueduct failure characteristics were summarized and analyzed based on failure living examples existing research results of numerical simulations and model tests. The typical failure characteristics of aqueducts caused by earthquake, high wind, flood and durability were summarized. The possible failure modes of the pile foundation, the support structure and the aqueduct body for aqueduct structures of simple supported beam typeswere mainly analyzed. Firstly, the failure modes of the pile foundation includes three types, insufficientsoilbearing, insufficient compression strength of the pile and the displacement of the pile tip exceeding limitingvalues. Secondly, bending or shear failure may occur at the pier-bottom. Shear failure may occur at the corbel. Failures tend to occur at the ends of a bent fame column and around the joints of a coupling beam. Thirdly, failure types of bending, shear or shear-bending may occur at the longitudinal beam. The end floor beams, the mid-span and ends of a bottom plate, the bottom of side walls, the bottom of rib plates and the upper tie bars are easy to be damaged. Furthermore, there are many durabilitydamages, such as cracks, concrete carbonation, concrete scaling, leakage, reinforcement corrosion and seal damage.
In order to simulate the aqueduct damage and evaluate the structure safety in a reasonable way, aqueduct failure characteristics were summarized and analyzed based on failure living examples existing research results of numerical simulations and model tests. The typical failure characteristics of aqueducts caused by earthquake, high wind, flood and durability were summarized. The possible failure modes of the pile foundation, the support structure and the aqueduct body for aqueduct structures of simple supported beam typeswere mainly analyzed. Firstly, the failure modes of the pile foundation includes three types, insufficientsoilbearing, insufficient compression strength of the pile and the displacement of the pile tip exceeding limitingvalues. Secondly, bending or shear failure may occur at the pier-bottom. Shear failure may occur at the corbel. Failures tend to occur at the ends of a bent fame column and around the joints of a coupling beam. Thirdly, failure types of bending, shear or shear-bending may occur at the longitudinal beam. The end floor beams, the mid-span and ends of a bottom plate, the bottom of side walls, the bottom of rib plates and the upper tie bars are easy to be damaged. Furthermore, there are many durabilitydamages, such as cracks, concrete carbonation, concrete scaling, leakage, reinforcement corrosion and seal damage.
2015,35(3):11-18, DOI: 10.3880/j.issn.1006-7647.2015.03.003
Abstract:
Fecal Coliform (FC) concentration in surface waters, such as, rivers, lakes, reservoirs and coastal areas, of China was surveyed based on literatures published since 1980s. From the survey, the temporal variation and the spatial distribution of FC concentration is analyzed, and then influencing factors on distribution characteristics of FC are systematically discussed. The results demonstrate that FC concentration is generally high throughout the surface waters in China, which indicates that the waters suffer a severe microbial contamination. Rivers are most severely contaminated among different water bodies while reservoirs are cleanest. The concentration of FC shows significant inter-annual and intra-annual fluctuations, with the concentration in wet seasons being much greater than that in dry seasons. There is no obvious distribution pattern of FC concentration between southern and northern waters, while the FC concentration in eastern areas is obviously greater than that in western areas. The FC concentration in lower reaches of rivers is greater than that in the upper reaches, and the FC concentration near shore is greater than offshore. These indicate that human actions significantly increase the concentration of FC. Rainfall-runoff has a significant impact on the temporal variation and spatial distribution of FC. Besides, many other physical-chemical factors, including organic content, trophic level, salinity, and temperature of water are also responsible for the spatial distribution and temporal variation of concentration of FC.
Fecal Coliform (FC) concentration in surface waters, such as, rivers, lakes, reservoirs and coastal areas, of China was surveyed based on literatures published since 1980s. From the survey, the temporal variation and the spatial distribution of FC concentration is analyzed, and then influencing factors on distribution characteristics of FC are systematically discussed. The results demonstrate that FC concentration is generally high throughout the surface waters in China, which indicates that the waters suffer a severe microbial contamination. Rivers are most severely contaminated among different water bodies while reservoirs are cleanest. The concentration of FC shows significant inter-annual and intra-annual fluctuations, with the concentration in wet seasons being much greater than that in dry seasons. There is no obvious distribution pattern of FC concentration between southern and northern waters, while the FC concentration in eastern areas is obviously greater than that in western areas. The FC concentration in lower reaches of rivers is greater than that in the upper reaches, and the FC concentration near shore is greater than offshore. These indicate that human actions significantly increase the concentration of FC. Rainfall-runoff has a significant impact on the temporal variation and spatial distribution of FC. Besides, many other physical-chemical factors, including organic content, trophic level, salinity, and temperature of water are also responsible for the spatial distribution and temporal variation of concentration of FC.
Journal information
- Competent unit：
教育部
- Organizers：
河海大学
- Editor-in-chief：
顾冲时
- Address：
南京西康路1号 河海大学《水利水电科技进展》编辑部
- Postcode：
210098
- Phone：
025-83786335
- Email：
jz@hhu.edu.cn
- CN：
32-1439/TV
- ISSN：
1006-7647
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Advances in Science and Technology of Water Resources ® 2024 All Rights ReservedAddress：南京 河海大学《水利水电科技进展》编辑部Postcode：210098Tel：025-83786335
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