基岩裸露率与土壤厚度对土壤流失影响的模拟试验

Simulation experiments on influences of bedrock exposed rate and soil thickness on soil erosion

为了研究岩溶地区基岩裸露率与土壤厚度对土壤流失的影响,利用自制的试验设备,开展了浅薄土壤下覆表层岩溶裂隙带水文过程及其驱动的土壤运移过程室内模拟试验研究。综合考虑岩溶二元水文地质结构下存在的土壤地表流失与地下漏失现象,结果表明地表和地下产沙速率随时间的变化先快速上升到峰值之后逐渐减小,地下产沙速率与土壤厚度呈显著正相关关系,地表产沙速率与基岩裸露率呈显著负相关关系,随着基岩裸露率的增大,地表产沙速率随时间的波动越来越明显;地表/地下产沙量与基岩裸露率/土壤厚度的相关性较好,线性相关性系数R2均达到了0.9以上。地表产沙量随着基岩裸露率、土壤厚度的增加而减小;而地下产沙量随着基岩裸露率的增大而减小、随着土壤厚度的增加而增大。

In order to study the influences of bedrock exposure rate and soil thickness on water and soil loss in karst areas,the simulation experiments are carried out to study the hydrological process and its driving water and soil movement process by the self-made test equipment.Considering the phenomenon of soil surface loss/underground leakage under karst hydrogeological structure,the results show that the characteristics of surface and underground soil loss rate are that the runoff rate rises rapidly to the peak value and then gradually decreases.There is a significant positive correlation between the soil underground leakage rate and the soil thickness,and a significant negative correlation between the soil surface loss rate and the bedrock exposure rate.With the increase of the bedrock exposure rate,the fluctuation of soil surface loss rate with time is more obvious.The correlations between the sediment yield and the bedrock exposure rate/soil thickness are fine,and the linear correlation coefficients R2 are all above 0.9.The surface sediment yield decreases with the increase of the bedrock exposure rate and soil thickness,and the underground sediment yield decreases with the increase of the bedrock exposure rate but increases with the increase of the soil thickness.