Freezing And Thawing Slope Erosion And Sediment Yield Process Based On Near-field Photogrammetry

Soil erosion has become one of the world's environmental hazards and one of the biggest environmental hazards in China.Efficient,convenient and rapid quantitative assessment of soil erosion processes and soil erosion is a fundamental step to prevent further soil erosion in China and to protect and rationally utilize land resources.In this paper,we will use close-range photogrammetry technology to compare the error and relationship between the measured and measured values,and study the process of erosion and sediment production under the conditions of runoff erosion.Firstly,the actual changes of soil erosion during the process of freezing and thawing slope erosion and sediment production under different flow,slope and thawing depth conditions were studied,which laid a solid foundation for the subsequent use of close-range photography to obtain soil erosion.The test results of the runoff plot indicate that:(1)Under the condition that the slope and the initial thawing depth are the same,the sediment yield of the frozen-thrusted slope increases with the flow rate,and the sediment yield increases with the scouring time.Gradually decrease,and finally stabilize;(2)Under the condition of the same flow rate and slope,the sediment yield of freeze-thaw slope increases with the increase of the initial thawing depth,and the sand production with time changes.The amount decreases and finally stabilizes;(3)When the flow rate and the initial thawing depth are the same,the sediment yield of the frozen-thrusted slope increases gradually with the increase of the slope,and the sediment yield increases with time.The amount is reduced,and finally stabilizes;(4)When the flow rate,the initial thawing depth,and the slope are maximum,the slope erosion and sediment yield reaches the maximum.This is because in the early stage of runoff erosion,there is a large amount of thawed soil on the surface of the slope.The soil is loose and easily eroded,so the soil erosion rate is faster in the first few minutes,but the water flow is washed off after the surface is thawed.It begins to erode the unthawed soil below,which is evenly hard and less susceptible to erosion.Therefore,the rate of soil erosion is significantly reduced afterwards and becomes more uniform and stable.Further,using close-range photogrammetry technology,the software Photo Modeler Scanner of the close-range photogrammetry system can obtain the changes of erosion and sediment yield profiles under different design parameters at different times.The profile images before and after erosion and sediment production were imported into Auto CAD 3D Civil software,and the changes in erosion and sediment yield with experimental parameters were calculated.A simple linear regression equation was used to fit the relationship between slope erosion and sediment yield and the measured erosion and sediment yield under the condition of runoff scouring.The linear regression equation can perfectly express the close-range photogrammetric value.The relationship between the measured values.The amount of sediment produced by the close-range photogrammetry technology can be processed through simple fixed error,and finally the accurate slope erosion and sediment yield can be obtained.In order to further explore the correlation between the three major factors of slope erosion and sediment yield and slope,flow and thawing depth,and the interaction between them,the interaction analysis method was used to study the measured values of slope erosion andsediment yield and the close-up A linear regression equation between the measured values of slope erosion and sediment yield obtained by photogrammetry.According to the measured values of sediment yield,the sediment yield is directly related to slope and runoff during slope erosion and sediment production under freezing and thawing conditions.The effect of slope on sediment yield is related to the depth of thawing,ie there is slope-thaw Deep interaction.Corresponding measurements of sediment yield obtained by close-range photography have been found to be directly related to runoff,while the effect of slope on sediment yield is related to the depth of thawing,ie,the interaction of slope-thaw depth effect.