Characteristics Of Saturated Hydraulic Conductivity Of Soil In Reclamation Dump Of Open Pit Coal Mine In Spring Thawing Period

The reclamation of the dump in an open-pit coal mine is a landform unit re-formed after soil structure is destroyed.Due to the special composition and arrangement of soil,its water distribution characteristics also have a certain degree of complexity and particularity.Freeze-thaw erosion is a special form of erosion that is inevitable in winter and spring in northern regions,and the snowmelt runoff produced by it has a great impact on dumps.At present,there are relatively few studies on the soil moisture of the dumping site of open-pit mines under freezing and thawing conditions.The characteristics of saturated hydraulic conductivity of the dumping site under different vegetation restoration modes under freezing and thawing conditions have been studied,and the main factors affecting the saturated hydraulic conductivity have been clarified.It is of great significance to the ecological restoration of industrial and mining areas in the north.This study takes different vegetation restoration patterns(elm woodland,torch woodland,agricultural land,waste grassland)and soil depth(0～20 cm,20～40 cm,40～60 cm)soil in the open-pit coal dump,Simulate the natural environment during the spring thawing period with relevant laboratory instruments,analyze the impact of thawing time and cycle times on soil moisture,and provide a scientific basis for formulating reasonable soil and water conservation measures during the spring thawing period in the region.the result shows:(1)There are significant differences in soil saturated hydraulic conductivity between different land uses and different soil depths.The saturated hydraulic conductivity of the 0～20 cm surface layer is higher,and it drops significantly after the freeze-thaw cycle,which can more accurately reflect the soil Freeze-thaw cycle process.(2)The change trend of soil physical indicators in the study area before and after freezing and thawing is not the same.The soil moisture content,non-capillary porosity,non-capillary porosity,and saturated hydraulic conductivity are all reduced to varying degrees.Before freezing and thawing,the saturated hydraulic conductivity of soil is significantly related to the porosity of soil capillary and non-soil capillary.After freezing and thawing,the saturated hydraulic conductivity of soil is significantly related to the soil moisture and non-soil capillary porosity.(3)The change of soil saturated hydraulic conductivity is affected by soil moisture content,capillary porosity,and non-capillary porosity.In addition,freezing and thawing,type of plot,depth of soil layer,freezing and thawing × depth of soil layer,and type of plot × depth of soil layer are also influencing factors of soil saturated hydraulic conductivity.(4)In the process of freezing and thawing cycles,the influencing factors of soil saturated hydraulic conductivity are cycle times,thawing time,freezing and thawing × plot type.The paper has 22 pictures,20 tables,and 74 references.