| Soil erosion seriously affects human production activities.How to effectively control soil erosion is a scientific problem that needs to be solved urgently for a long time.In the hot and dry valley area,the climate in the dry and wet seasons is significantly different.The rainy season is heavy and concentrated,and the dry season is less rainy,which makes the local soil erosion problem serious.Consolidation terrace slopes are prone to gully erosion under the combined action of multiple factors.To find out the morphological features and influencing factors of consolidation terrace slope erosion gully,field measurements and laboratory analysis methods were used in this study to obtain the consolidation terrace slope erosion in the study area.Data related to morphological features and geochemical properties of soil,based on data processing methods such as regression correlation,mainly to study the morphological features of slope erosion gully,the physical and chemical properties of soil,and the influence of physical and chemical properties of geotechnical properties on morphological features,to provide a research base for the dry-hot valley area.Provide a reference for a selection of consolidation terrace slope repair and control measures.The main conclusions of this study are as follows:(1)Morphological features of the eroded gully of consolidation terrace slope.(1)The study of the morphological characteristics of the erosion gully shows that: The maximum perimeter is Plot 5(74.54m),and its branch gully is not completely merged with the main gully,resulting in a complicated gully along the line;There is a significant difference ithe n area,the maximum value is Plot 1(47.92m2),and the minimum value is Plot 5(25.62m2);Plot 1 has the longest gully length(4.6m),and the retrograde erosion at the head of the gully is the strongest;the volume of Plot 1(22.39m3)Much larger than Plot 5(2.24m3),the erosion scale of Plot 1 is much larger than that of Plot 5.The classification result of rupture status is that the surface rupture degree of Plot 1 belongs to the strong rupture type;Plot 2,Plot 3,and Plot 4 belong to the moderate rupture type;Plot 5 belongs to the mild rupture type.The gully density classification results showed that Plot 5 belonged to the complex distribution type;Plot 1,Plot 2,and Plot 4 belonged to the relatively complex distribution type;Plot 3 belonged to the relatively simple distribution type.The morphological index classification results showed that Plot 1～Plot 4 belonged to the more complex morphological type,and Plot 5 belonged to the morphologically complex type.The fractal dimension of the gully varies from 1.0766 to 1.1691,and its correlation coefficients are all above 0.99,which has a good fitting effect.(2)The research on the morphological characteristics of the cross-section of the erosion gully in the study area shows that: the depth,width,area,and perimeter of the gully in the cross-section all show a downward trend with the increase of the slope length.The gully width to depth ratio is greater than 1,and the lateral erosion is stronger than the downward erosion;in the gully shape index(0.08～0.69),the value of the gully mouth increases,and the gully bottom gradually becomes flat;in the gully area asymmetry(0.2628～9.3417),there are 15 leftdip cross-sections,16 right-dip cross-sections,and 3 quasi-symmetric cross-sections the gully concavity index shows that the average value of Plot 4 is the largest(1.04),and the overall gully activity is the highest.3 The mean is the smallest(0.64)and the activity intensity is the lowest.(3)Using principal component analysis to obtain the gully erosion development index Q,observe its distribution and obtain the overall erosion situation of the gully(strong→weak)Plot 1>Plot 4>Plot 2>Plot 3>Plot 5.(2)Influence factors of consolidation terrace slope erosion gully.(1)Geophysical property factors: the soil bulk density(1.30～1.33g/cm3)at the head of the gully is larger than that in the middle of the gully(1.24～1.29g/cm3);Greater than the gully(1.29 ±0.03g/cm3).The soil water content is very low(2.69%～11.44%),and the field water holding capacity fluctuates greatly(20.63%～41.42%).The saturated water content in the gully(23.17%～45.61%)is higher than that of the debris accumulation.The total soil porosity varies significantly in different parts(37.43%～55.57%),the total porosity of the gully is larger than that of the accumulation body;the capillary porosity fluctuates little(26.80%～41.83%);the non-capillary porosity is small(10.63%～41.83%)The ratio of capillary porosity to non-capillary porosity is 2.33 on average,and the water permeability and water holding capacity of the gully and debris accumulation is well coordinated.In the soil mechanical composition,from more to less,they are sand(71.35%～77.86%),silt(16.57%～22.89%),and clay(5.57%～6.35%),which is sandy loam,suitable for droughtresistant,Barren-tolerant plants;the fractal dimension of soil particle size is not high,and the soil quality is loose.(2)Geochemical properties factors: the p H value of the soil in each gully is greater than 7.5,and the soil is alkaline.The soil organic matter content showed that Plot 4 was the highest(1.77g/kg),the lowest in Plot 2(0.42g/kg),and the average was 1.24g/kg.The organic matter content varied greatly in different parts of the trench.(3)Other influencing factors: Precipitation,as the main driving force of soil erosion,causes slope gully erosion by splashing the ground;while the roots of vegetation pass through the fixed soil,they may also exacerbate slope gully erosion through root splitting and rhizosphere biological secretion.Soil erosion;anthropogenic grazing will cause crusts to form on the surface of the slope,affecting water infiltration,and frequent trampling may also damage the surface,thereby affecting the morphological and developmental features of the eroded gully;terrain factors include slope(especially critical slope),slope The aspect and slope length,etc.,also have an important impact on the morphological and developmental features of the slope gully.(3)Morphological features of consolidation terrace slope erosion gully and its influencing factors.(1)Geophysical properties affect the plane shape features of eroded trenches: the total porosity has a positive effect on the shape index,indicating that the greater the total soil porosity,the more complex the plane shape index of the trench;the soil bulk density has a significant negative effect on the density and perimeter along the trench.The influence relationship shows that the smaller the soil bulk density,the more complex the gully plane shape.The field water capacity has a significant negative effect on the perimeter,the density along the gully,and the shape index,indicating that the field water capacity has a certain influence on the complexity of the eroded gully shape.(2)Geophysical properties affect the morphological features of the cross-section of the eroded gully: the natural water content in the geophysical properties has a significant positive effect on the width-depth ratio of the cross-section and the shape index of the cross-section,indicating that within a certain threshold range,the higher the soil water content high,the lateral erosion is more serious than the downward erosion,and the slope is more stable;the natural water content has a significant negative effect on the crosssection gully depth,gully width,perimeter,area and concavity,indicating that the lower the soil water content,the better the gully.The more severe the erosion.(3)Geochemical properties affect the morphological features of eroded gully: The chemical properties of rock and soil have no significant effect on the indicators of plane shape and crosssectional shape.Significantly affected.(4)Other factors affect the morphological features of the erosion gully: The morphological features of the erosion gully are affected by many factors.Under the condition of heavy rainfall,the erosion effect of the erosion gully increases,resulting in the growth of the gully tail;the slope factor will significantly affect the slope erosion intensity and affect the width of the gully.Deep development,the slope ratio of the gully affects the length of the eroded gully and the area of the gully system,which increases first and then decreases with the increase of the slope,and the width of the erosion gully generally increases with the increase of the slope;good vegetation coverage includes It is beneficial to slow down the development of gully undercut erosion;the choice of ridge orientation during artificial farming will also affect the development of gully erosion. |
PDF Full Text Request