A shear impact energy model （SIEM） of erosion suitable for both dilute and dense particle flows is pro- posed based on the shear impact energy of particles in discrete element method （DEM） simulations. A number of...A shear impact energy model （SIEM） of erosion suitable for both dilute and dense particle flows is pro- posed based on the shear impact energy of particles in discrete element method （DEM） simulations. A number of DEM simulations are performed to determine the relationship between the shear impact energy predicted by the DEM model and the theoretical erosion energy. Simulation results show that nearly one-quarter of the shear impact energy will be converted to erosion during an impingement. According to the ratio of the shear impact energy to the erosion energy, it is feasible to predict erosion from the shear impact energy, which can be accumulated at each time step for each impingement during the DEM simulation. The total erosion of the target surface can be obtained by summing the volume of material removed from each impingement. The proposed erosion model is validated against experiment and results show that the SIEM combined with DEM accurately predicts abrasive erosions.展开更多
Submarine landslides can cause severe damage to marine engineering structures. Their sliding velocity and runout distance are two major parameters for quantifying and analyzing the risk of submarine landslides.Current...Submarine landslides can cause severe damage to marine engineering structures. Their sliding velocity and runout distance are two major parameters for quantifying and analyzing the risk of submarine landslides.Currently, commercial calculation programs such as BING have limitations in simulating underwater soil movements. All of these processes can be consistently simulated through a smoothed particle hydrodynamics（SPH） depth integrated model. The basis of the model is a control equation that was developed to take into account the effects of soil consolidation and erosion. In this work, the frictional rheological mode has been used to perform a simulation study of submarine landslides. Time-history curves of the sliding body＇s velocity, height,and length under various conditions of water depth, slope gradient, contact friction coefficient, and erosion rate are compared; the maximum sliding distance and velocity are calculated; and patterns of variation are discussed.The findings of this study can provide a reference for disaster warnings and pipeline route selection.展开更多
Soil erosion is a serious threat to soil and water resources in semi-arid regions.Modified Pacific Southwest Inter Agency Committee(MPSIAC)and Erosion Potential Method(EPM),as two well-known models,have shown their pe...Soil erosion is a serious threat to soil and water resources in semi-arid regions.Modified Pacific Southwest Inter Agency Committee(MPSIAC)and Erosion Potential Method(EPM),as two well-known models,have shown their performance in many case studies.The goal of present study is to assess the efficiency of these methods for estimating the sediments yield and erosion intensity within short-term and longterm timeframes over two sub-basins of Dez watershed,west of Iran.The results showed that the study area can be categorized into slight,moderate,high and very high erosion zones.Almost half of the study area is highly susceptible to erosion due to the geological formations and land cover.Moreover,the longterm(i.e.30 years)sediment yield of 387 and 615(kton)y^(-1) estimated by MPSIAC and EPM models demonstrated the superiority of EPM.Compared to the measured value of 612(kton)y^(-1),the performance of EPM was astonishing.By splitting the dataset into six periods of five years,the sediment yield was predicted in short-term periods by both aforementioned methods.Such segmentation provides the opportunity to evaluate the impact of extreme flooding events on the models performances.The results showed that both models failed in estimation of sediment load during flood conditions.Nevertheless,the correlation coefficients for estimating the sediment yield were found to be R=0.93 and R=0.85 for EPM and MPSIAC models respectively,for short-term simulations.展开更多
文摘A shear impact energy model （SIEM） of erosion suitable for both dilute and dense particle flows is pro- posed based on the shear impact energy of particles in discrete element method （DEM） simulations. A number of DEM simulations are performed to determine the relationship between the shear impact energy predicted by the DEM model and the theoretical erosion energy. Simulation results show that nearly one-quarter of the shear impact energy will be converted to erosion during an impingement. According to the ratio of the shear impact energy to the erosion energy, it is feasible to predict erosion from the shear impact energy, which can be accumulated at each time step for each impingement during the DEM simulation. The total erosion of the target surface can be obtained by summing the volume of material removed from each impingement. The proposed erosion model is validated against experiment and results show that the SIEM combined with DEM accurately predicts abrasive erosions.
基金The Specialized Research Fund for the Doctoral Program of Higher Education under contract No.20120041130002the National Key Project of Science and Technology under contract No.2011ZX 05056-001-02the Fundamental Research Funds for the Central Universities under contract No.DUT14ZD220
文摘Submarine landslides can cause severe damage to marine engineering structures. Their sliding velocity and runout distance are two major parameters for quantifying and analyzing the risk of submarine landslides.Currently, commercial calculation programs such as BING have limitations in simulating underwater soil movements. All of these processes can be consistently simulated through a smoothed particle hydrodynamics（SPH） depth integrated model. The basis of the model is a control equation that was developed to take into account the effects of soil consolidation and erosion. In this work, the frictional rheological mode has been used to perform a simulation study of submarine landslides. Time-history curves of the sliding body＇s velocity, height,and length under various conditions of water depth, slope gradient, contact friction coefficient, and erosion rate are compared; the maximum sliding distance and velocity are calculated; and patterns of variation are discussed.The findings of this study can provide a reference for disaster warnings and pipeline route selection.
基金The authors wish to thank the Khuzestan Water and Power Authority for data sharing.The Arca Company is also acknowledged for their GIS support.The authors also thank valuable comments made on an earlier draft from M.N.Allahdadi,Louisiana State University。
文摘Soil erosion is a serious threat to soil and water resources in semi-arid regions.Modified Pacific Southwest Inter Agency Committee(MPSIAC)and Erosion Potential Method(EPM),as two well-known models,have shown their performance in many case studies.The goal of present study is to assess the efficiency of these methods for estimating the sediments yield and erosion intensity within short-term and longterm timeframes over two sub-basins of Dez watershed,west of Iran.The results showed that the study area can be categorized into slight,moderate,high and very high erosion zones.Almost half of the study area is highly susceptible to erosion due to the geological formations and land cover.Moreover,the longterm(i.e.30 years)sediment yield of 387 and 615(kton)y^(-1) estimated by MPSIAC and EPM models demonstrated the superiority of EPM.Compared to the measured value of 612(kton)y^(-1),the performance of EPM was astonishing.By splitting the dataset into six periods of five years,the sediment yield was predicted in short-term periods by both aforementioned methods.Such segmentation provides the opportunity to evaluate the impact of extreme flooding events on the models performances.The results showed that both models failed in estimation of sediment load during flood conditions.Nevertheless,the correlation coefficients for estimating the sediment yield were found to be R=0.93 and R=0.85 for EPM and MPSIAC models respectively,for short-term simulations.
