矿区废石场覆土层垂直侵蚀特征的初步分析

研究选择云南大红山铁矿,采用人工模拟降雨技术,首次对矿区废石场覆土层垂直侵蚀进行了实验研究,初步发现了垂直侵蚀的主要特征.研究表明,垂直侵蚀造成覆土层土壤向下迁移,除小部分截留在废石中,大部分成为土壤损失冲带到更深层废石中;垂直侵蚀随降雨强度、降雨历时的增加而增加,不同土壤的侵蚀临界降雨量不同;垂直侵蚀与土壤渗透呈高度的正相关关系,还与土壤含砂量、孔隙度、通气度呈正相关,与土壤含水量呈负相关;实验发现,垂直侵蚀可以分为土相渗蚀和岩气相冲蚀2种形态,发生方式不同,前者的发生过程分成土壤润湿、强度侵蚀、侵蚀减弱3个典型阶段,三者水动力条件不同;垂直侵蚀一旦发生,可能导致极强度土壤侵蚀,造成十分严重的水土流失.

A Preliminary Analysis on the Characteristics of Vertical Erosion of overlaid Soil in Mullock Field in Mining Areas

The result of the experimental study of vertical erosion of overlaid soil in mullock field in mining areas is demonstrated.Take Dahongshan Mine area as an example.It shows that the vertical erosion does happen and cause a big portion of soil lost from the shallow waste stones layer.The extent of vertical erosion increases with precipitation,rainfall intensity and soil infiltration rates,and different soil has different critical rainfall amount.The study also shows that vertical erosion can be divided into two main types.The study is focused on three stages: soil wetting stage,intensity erosion and erosion decrease.Each of them is driven by different hydrolic conditions.Once the erosion takes place,vast amount of soil erosion will happen.