喀斯特地区裸坡面土壤侵蚀的人工模拟降雨试验研究

Bare Slope Soil Erosion Experimental Research Under the Condition of Artificial Rainfall Precipitation in Karst Area

通过人工模拟喀斯特裸坡面微地貌特征和地下喀斯特裂隙构造,结合人工模拟降雨实验,研究不同基岩裸露率、不同降雨强度、不同地下孔裂隙度以及降雨历时对土壤侵蚀的影响。结果表明:(1)地表、地下孔裂隙流量均随雨强的增大而增大,地表累积悬移质和推移质流失量,地下累积悬移质流失量均随雨强的增大总体呈增大的变化规律;(2)总体上地表径流随基岩裸露率的增大先增大后减小,地下孔裂隙流随基岩裸露率的增大先减小后增大;地表累积推移质和悬移质流失量随基岩裸露率的增大总体呈增大趋势,地下孔裂隙流的累积悬移质流失量随基岩裸露率的增大总体呈减小的变化规律;(3)降雨历时和地表径流呈正相关的关系,而和地下孔裂隙流则呈负相关的关系;地表的推移质和悬移质产沙量,地下孔裂隙的产沙量随降雨历时总体呈下降趋势;(4)地表产流产沙随地下孔裂隙度增大而减小,而地下产流产沙则相反;(5)土壤侵蚀和各因子间相关程度为雨强>降雨历时>地下孔裂隙度>基岩裸露率。

Combined with the artificial rainfall experiments, researched the effects of different rates of exposed bedrock, different rainfall intensity, different degrees of underground holes and fissures and rainfall duration on the soil erosion by the manual simulation of micro topographical features of the Karst bare slope and the fractured structure of underground Karst. The results showed. （1）The flow of both the surface and underground holes fracture increased with increasing the rainfall intensity, as well as the loss of the surface accumulation of suspended sediment and bedload. （2）As a whole, surface runoff firstly increased and then decreased with the increase of the rates of exposed bedrock, while the flow of underground hole crack was opposite. Furthermore, the loss of the surface accumulation of suspended sediment and bedload increased with the increase of the rates of exposed bedrock. However, the suspended load flow of the underground hole crack was opposite. （3） The rainfall duration separately showed a positive and a negative correlation with surface runoff and the flow of underground hole crack respectively. （4） Surface runoff and sediment yield decreased with the increase of the underground hole crack, and the underground runoff and sediment yield was opposite. （5）The degree of correlation between soil erosion and each factor was rainfall intensity 〉rain time 〉degrees of underground holes and fissures 〉ratios of uncovered rocks.