Study On Erosion Characteristics Of Different Types Of Dumped Soil

With the rapid development of China's economy,ensuing the great development and achievements on the all kinds of production and construction projects.At the same time,a lots of production and construction projects dumped soil and the various disturbed soil underlying surfaces of production and construction projects had been generated.Loose structure and strong water permeability are the characteristics of the composition of the dumped soil.Therefore,compared with the dumped soil erosion and the original erosion,the total erosion of the former is much larger than that of the latter.Strong explosive,various forms of soil and water loss,severe soil and water loss intensity,great destructive are the characteristics of slope erosion of dumped soil.Meanwhile,those bring serious challenges to the environment of human survival.In this paper,we studied 4 typical dumped soil derived from different parent materials in south china?red soil derived from granite,red soil derived from red sandstone,red soil derived from quaternary red clay,purple soil derived from purple sand shale?.The dumped soil is produced by the production and construction projects.We have used the method of simulating runoff plot to observe runoff and sediment data for two years?2014and2015?under natural rainfall conditions.Firstly,we have analyzed the relationship between water and sediment and rainfall parameters in different types of dumped soil.Secondly we have adopted 3 kinds of plant measures in the runoff plot?Topsoil cover and sowing grass and shrub,sowing grass and shrub,CK?,and discussed the effect of the two kinds of plant measures on runoff and sediment of dumped soil slope.In the end,we have studied the dynamic developmental characteristics of dumped soil slope rill erosion,studied the soil erodibility of dumped soil.In order to provide scientific guidance for the prediction of soil erosion and similar project preparation for production and construction projects.The main conclusions are as follows:?1?Distribution of rainfall in the year in the experimental area is a single peak type distribution;4-7 month is the peak interval;the erosive rainfall accounts of intermittent B type rainfall and large rainfall and longtime C type rainfall for more than 80%of the total erosive rainfall amount.The runoff volume and erosion amount of the four different types of dumped soil are extremely significant positive correlation with rainfall amount.In the three rain type,the runoff of each type of abandoned soil can be expressed by the linear function of rainfall amount.A rain type,the amount of soil erosion in each type of dumped soil can be used to express the linear function of rainfall?average rain intensity?,but there was no significant linear relationship between the amount of eroded sediment and the precipitation?rain intensity?of B and C rainfall type.Inter annual variation of runoff volume and the amount of soil erosion are affected by the change of vegetation.?2?The maximum ratio of runoff volume and rainfall amount in the exposed area under the A rain type.The ratio runoff volume and rainfall amount of a small area with plant measure is larger than that of the exposed area under the B and C rain type,this may be related to the grass surface runoff under the rain type.In addition there are significant differences between the purple soil overburden spoil sowing area and sowing area,the rest of the types of abandoned soil,rain type and plant measures did not cause significant differences in ratio of runoff volume and rainfall amount.The maximum ratio of sediment yield and rainfall amount in the exposed area under the A rain type.There was no obvious law of the ratio of sediment yield and rainfall amount in the area with plant measures under the B and C rain type.The difference of the ratio of sediment yield and rainfall amount is significant between different measures,but difference between the rain types is not significant?red dumped soil derived from granite,red dumped soil derived from red sandstone?.Both the measures and the rain type have a significant effect on the ratio of sediment yield and rainfall amount?red dumped soil derived from quaternary red clay?.There was no significant difference in sediment yield and rainfall amount ratio between the measures and the rain type?purple dumped soil derived from purple sand shale?.?3?The cumulative gully erosion amount in the exposed area is red dumped soil derived from red sandstone>red dumped soil derived from granite>purple dumped soil derived from purple sand shale>red dumped soil derived from quaternary red clay,and there was a significant difference in the gully erosion amount between the red dumped soil derived from red sandstone and the other three soil type.The average gully erosion amount is the percentage of the average total amount of erosion in the individual rainfall?red dumped soil derived from red sandstone>red dumped soil derived from quaternary red clay>red dumped soil derived from granite>purple dumped soil derived from purple sand shale>?,and there was a significant difference between red dumped soil derived from red sandstone and the other three types.The amount of gully erosion is consistent with the change of rainfall in the individual rainfall?red dumped soil derived from red sandstone and red dumped soil derived from quaternary red clay?,and they have a significant regression.The correlation between gully erosion amount and rainfall amount is not obvious?red dumped soil derived from granite and purple dumped soil derived from purple sand shale?.There was a significant positive correlation between the amount of gully erosion and rainfall intensity in the individual rainfall?purple dumped soil derived from purple sand shale?.The correlation between the gully erosion amount of the other three kinds of dumped soil and the average rainfall intensity is not obvious.?4?A significant positive correlation was observed between rainfall erosivity and rainfall amount in the individual rainfall.The rainfall erosivity can be expressed by the power function of the rainfall amount.The soil erodibility K values obtained by the runoff plot method are 0.03748 t·hm²·h·hm^-2·MJ^-1·mm^-1?red dumped soil derived from granite and CK?,0.00357 t·hm²·h·hm^-2·MJ^-1·mm^-1?red dumped soil derived from granite and topsoil cover and sowing grass and shrub?,0.00837 t·hm²·h·hm^-2·MJ^-1·mm^-1?red dumped soil derived from granite and sowing grass and shrub?,0.05875 t·hm²·h·hm^-2·MJ^-1·mm^-1?red soil derived from red sandstone and CK?,0.00582 t·hm²·h·hm^-2·MJ^-1·mm^-1?red soil derived from red sandstone and topsoil cover and sowing grass and shrub?,0.02537t·hm²·h·hm^-2·MJ^-1·mm^-1?red soil derived from red sandstone and sowing grass and shrub?,0.01246 t·hm²·h·hm^-2·MJ^-1·mm^-1?red soil derived from quaternary red clay and CK?,0.00549 t·hm²·h·hm^-2·MJ^-1·mm^-1,?red soil derived from quaternary red clay and topsoil cover and sowing grass and shrub?,0.00133 t·hm²·h·hm^-2·MJ^-1·mm^-1?red soil derived from quaternary red clay and sowing grass and shrub?,0.01389 t·hm²·h·hm^-2·MJ^-1·mm^-1?purple soil derived from purple sand shale and CK?,0.00317t·hm²·h·hm^-2·MJ^-1·mm^-1?purple soil derived from purple sand shale and topsoil cover and sowing grass and shrub?.The soil erodibility K value in a plot with plant coverage is smaller than that of the exposed area.