[Objective] The aim was to select a cultivation method suitable for sandy lands in Liaoning Province. [Method] The research explored effects of autumn plowing, autumn rotary cultivation, autumn ridging, and rotary cul...[Objective] The aim was to select a cultivation method suitable for sandy lands in Liaoning Province. [Method] The research explored effects of autumn plowing, autumn rotary cultivation, autumn ridging, and rotary cultivation before spring sowing on physical and chemical properties. [Result] By autumn plowing, surface soils were seriously eroded, more water was evaporated, and more nutrients lost; by autumn rotary cultivation, surface soils were seriously eroded also, reducing wa- ter content and nutrients; by autumn ridging, surface soils were slightly eroded, so that evaporation was light and fewer nutrients lost; by rotary cultivation before spring sowing, soil erosion was the lightest, with more water and nutrients maintained. [Conclusion] It is effective for improving anti-wind erosion by no-tillage during fallow period and land reclamation before sowing in semi-dry areas.展开更多
For the basins with debris flow development,its channel terrain exhibits a tortuous shape,which significantly restricts the movement of debris flows and leads to severe erosion effects on the concave bank.Therefore,th...For the basins with debris flow development,its channel terrain exhibits a tortuous shape,which significantly restricts the movement of debris flows and leads to severe erosion effects on the concave bank.Therefore,this study aims to analyze the shear force of debris flows within the bend channel.We established the relationship between the shear force and bend curvature through laboratory experiments.Under the long-term erosion by debris flows,the curvature radius of bends gradually increases,however,when this increasing trend reaches an equilibrium state with the intensity of debris flow discharge,there will be no significant change in curvature radius.In general,the activity pattern and discharges of debris flows would remain relatively stable.Hence,we can infer the magnitude of debris flow discharges from the terrain parameters of the bend channel.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
文摘[Objective] The aim was to select a cultivation method suitable for sandy lands in Liaoning Province. [Method] The research explored effects of autumn plowing, autumn rotary cultivation, autumn ridging, and rotary cultivation before spring sowing on physical and chemical properties. [Result] By autumn plowing, surface soils were seriously eroded, more water was evaporated, and more nutrients lost; by autumn rotary cultivation, surface soils were seriously eroded also, reducing wa- ter content and nutrients; by autumn ridging, surface soils were slightly eroded, so that evaporation was light and fewer nutrients lost; by rotary cultivation before spring sowing, soil erosion was the lightest, with more water and nutrients maintained. [Conclusion] It is effective for improving anti-wind erosion by no-tillage during fallow period and land reclamation before sowing in semi-dry areas.
基金funded by the National Natural Science Foundation of China(Grant No.42201095)the Second Tibetan Plateau Scientific Expedition and Research(STEP)Program(Grant No.2019QZKK0902)the Postdoctoral Special Funding Project of Sichuan Province(Funding No.TB2023028).
文摘For the basins with debris flow development,its channel terrain exhibits a tortuous shape,which significantly restricts the movement of debris flows and leads to severe erosion effects on the concave bank.Therefore,this study aims to analyze the shear force of debris flows within the bend channel.We established the relationship between the shear force and bend curvature through laboratory experiments.Under the long-term erosion by debris flows,the curvature radius of bends gradually increases,however,when this increasing trend reaches an equilibrium state with the intensity of debris flow discharge,there will be no significant change in curvature radius.In general,the activity pattern and discharges of debris flows would remain relatively stable.Hence,we can infer the magnitude of debris flow discharges from the terrain parameters of the bend channel.
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.
