不同碎石含量的土壤降雨入渗和产沙过程初步研究

碎石的存在改变了均质土壤的某些物理特性，降雨入渗和侵蚀产沙过程也因此受到影响，获取相关知识有助于模拟和预测土石混合介质中发生的水土过程。试验在模拟降雨条件下，对4种不同碎石含量(质量含量分别为0%，10%，20%和30%)的土壤入渗和产沙过程进行了室内研究。结果表明，碎石含量为10%时，土壤入渗率最大，当碎石含量超过10%时，入渗率反而降低；4种不同碎石含量的土壤侵蚀产沙高峰期均出现在降雨初期0～20 min，此后土壤侵蚀产沙相对稳定且在不同碎石含量的土壤间差别不大；降雨过程中，10%碎石含量的土壤侵蚀含沙率一直保持稳定较低水平，其他碎石含量的土壤侵蚀含沙率起初很高并在0～10 min内急剧下降，此后与10%碎石含量的土壤侵蚀含沙率接近。

Processes of rainfall infiltration and sediment yield in soils containing different rock fragment contents

The presence of rock fragment has effects on some physical properties for homogeneous soil.As a result the processes of rainfall infiltration and sediment yield are changed.Knowledge of the processes affected by rock fragment is benefit to simulate and predict soil and water processes in stony-soil media.On the conditions of rainfall simulation,laboratory soils with four different rock fragment contents(gravimetric contents were 0%,10%,20%,and 30%,respectively) were constructed to study the processes of rainfall infiltration and sediment yield as affected by rock fragment.Results show that the maximum of infiltration rate presented at the rock fragment content was 10%,while the rock fragment content exceeded 10% the infiltration rate reduced on the contrary.The initial 0~20 min was the peak of sediment yields for four laboratory soils.After this sediment yields kept relatively steady and had hardly difference among four laboratory soils.During rainfall sediment concentration for soil with 10% rock fragment content held steady and at low level,and other laboratory soils were high at the beginning of rainfall and reduced remarkably within 0~10 min and then close to that of soil with 10% rock fragment content.