Experimental Study on Soil Erosion and Sediment Yield of

Abstract

 通过对生产建设项目弃土堆置体的野外调查及抽象概化,将抽象概化出的4类弃土堆置体作为研究对象,在室内模拟降雨条件下对不同弃土堆置类型的侵蚀产沙过程进行试验研究。结果表明:各类型弃土堆置体的入渗率、径流含沙量随降雨时间变化呈波动式减小,径流率随降雨时间变化呈波动式增大,侵蚀速率随降雨时间变化呈平缓型、多峰型2种变化趋势;产流时间与降雨强度呈负幂函数关系,平均入渗率、平均径流率、平均侵蚀速率与降雨强度呈线性关系,平均径流含沙量与降雨强度呈指数函数关系,总产沙量与总径流量呈线性关系。坡顶平台有车辆碾压的倾倒堆置在全部设计降雨强度条件下产流时间最短、平均入渗率均最低;当降雨强度从1.5mm/min提高到2.0mm/min时,总产沙量增大2.58倍,在降雨强度为2.0,2.5mm/min情况下,平均径流含沙量、平均侵蚀速率均明显大于其他堆置类型,且差异达到显著水平(P<0.05)。Abstract:Based on the field investigation and generalization of the development construction project ofspoilbanks,according to generalized results,four different types of spoilbanks were selected as researchobjects.The soil erosion and sediment yield process of four types were simulated in indoor rainfall experimentalcondition.The results were given in the following,the infiltration rate and sediment concentration of allspoilbanks decreased in a fluctuating tendency with the rainfalls time,while the runoff rate increased in afluctuating tendency with the rainfalls time.The variation of erosion sediment and transport rate appeared intwo types with the rainfalls time,which were smooth and multimodal distribution.Runoff generation timehad a negative exponent relation to rainfall intensity.Rainfall intensity had a linear function with averagerunoff rate,average erosion sediment and transport rate,respectively.Average sediment concentration hadexponential function relation to rainfall intensity,while total sediment yield and runoff volume accorded withlinear correlation.The type of rolling compaction by construction machinery at the top of slope had theshortest runoff generation time and lowest average infiltration rate in all design conditions of rainfall intensity.The total sediment yield increased 2.58times with rainfall intensities increasing from 1.5mm/min to 2.0mm/min.Under the rainfall intensity with 2.0mm/min and 2.5mm/min,the average sediment ratio ofrunoff and average erosion sediment rate were higher than that of other spoilbanks and their difference wassignificant(P<0.05)

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