摘要
弃土弃渣水土流失量预测是生产建设项目水土流失监测的重要内容。通过室内人工模拟降雨试验,模拟建设项目侵蚀强度与弃土弃渣在不同降雨条件下石块出露面积和土壤粗化的关系,探讨弃土弃渣坡面产流产沙量预测方法。在不同雨强(0.7、1.0、1.5 mm/min)和坡度(5°、15°、25°)组合的9种情况下,研究了降雨侵蚀过程,以及降雨前后单位面积石块出露变化量、表层土石混合物中石块所占比例、侵蚀强度与降雨前后表层土石混合物中石块所占比例差值之间的关系。结果表明:不同坡度、雨强条件下产流率随降雨时间推移均呈先增大后逐渐趋于平稳的趋势,两者之间的关系可用幂函数方程描述;不同坡度、雨强条件下含沙量均在产流后4 min和10 min左右出现峰值,16 min后基本平稳;降雨侵蚀导致土壤中细小颗粒被剥蚀,石块逐渐出露,侵蚀强度与单位面积石块出露变化量之间呈线性正相关关系;侵蚀强度与降雨前表层土石混合物中石块所占比例之间呈指数负相关关系;侵蚀导致分选作用,使得表层土壤粗化,不同雨强、坡度下侵蚀强度与降雨前后表层土石混合物中石块所占比例差值之间呈线性正相关关系。
Soil and water loss prediction of waste soil and residue is one of core contents in soil and water loss monitoring of production and construction projects.The paper simulated the relationship between erosion intensity and the exposed area of stone and soil coarsening under the different conditions of rainfall of a construction project by using indoor artificial simulation of rainfall and discussed methods for forecasting the runoff and sediment yields of waste soil and residues.It studied the process of rainfall erosion,the variation of unit exposed area of stone before and after rainfall,stone ratio of surface soil-stone mixture and the relationship between erosion intensity and proportion difference of stone of surface soil-stone mixture before and after rainfall through 9 groups rainfall tests of different combinations of rainfall intensity（0.7,1.0 and1.5 mni/min） and slope gradients（5°,15° and 25°）.The outcomes show that a） the runoff yield rate shows the trend of first increase then becoming stable along with the rainfall time under the different conditions of slope and rainfall intensity.The relationship of the two can be described by power functions;b） under the different conditions of slope and rainfall intensity,the sediment concentration shows its peak value at about 4 min and 10 min after runoff producing and it becomes stable after 16 min;c） owing to rainfall erosion,the fine particles of soil are denuded,stones exposed gradually and the variation of erosion intensity and unit exposed area of stone shows linear positive correlation;d）erosion intensity and the proportion of stone of surface soil-stone mixture before rainfall shows exponential negative correlation and;e） erosion leads to sorting and surface soil roughening.Erosion intensity and the proportion difference of stone of surface soil-stone mixture before and after rainfall under the different conditions of rainfall intensity and slopes shows linear positive correlation.
出处
《中国水土保持》
2016年第5期30-34,77,共5页
Soil and Water Conservation in China
基金
国家自然科学基金项目(41371273)
西北农林科技大学科技创新项目(QN2011152)
关键词
模拟降雨
弃土弃渣
石块出露量
石块比例
侵蚀强度
simulated rainfall
waste soil and residue
exposed area of stone
stone ratio
erosion intensity
