堆存时间对开发建设工程弃土流失特征的影响

工程弃土是开发建设项目新增水土流失的重要来源。以沈阳农业大学水利学院综合试验基地扩建工程弃土为研究对象,研究弃土堆存时间对其坡面产流产沙特征的影响。试验在沈阳农业大学水利学院综合试验基地的人工模拟降雨大厅内进行。共设置5个雨强,分别为0.64,0.82,1.05,1.24,1.52mm/min;5个堆存时间,分别为新堆积、3个月、6个月、9个月、12个月。研究结果表明,随着弃土堆积时间的增长,堆积1年的弃土抗剪强度、含水率及植被覆盖度均最大,分别为0.35kg/cm2,14.3%和10%,土体细粒成分最低,抵抗水流冲击破坏的能力最强。对于同一降雨强度,新堆积的弃土径流量最小,随着堆存时间延长,不断增加,最后趋于平稳;在不同降雨条件下,坡面含沙率随弃土堆存时间的增长而呈现波动性降低,坡面累计产沙量均随弃土堆存时间的增长而逐渐降低。

Effects on Stockpiling Time to Development Projects Abandon Soil Erosion Characteristics

Engineering abandon soil is important source of the new increase of soil and water loss of development projects.This article studied that brown earth abandon soil stockpiling time had an influence on slope sediment production abortion characteristics,which took expansion project abandon soil of comprehensive test base of water conservancy college of Shenyang agriculture university as the research object.Erosion and sediment yield process of soil dumped by people had been analyzed by simulated rainfall experiments.Rainfall intensity was set as 0.64,0.82,1.05,1.24,1.52 mm/min,and stockpiling time was set as new accumulation,3 months,6 months,nine months and 12 months.The results showed that with abandon soil stockpiling time increasing,shearing strength,moisture content and vegetation coverage of abandon soil which accumulated one year were the biggest,respectively 0.35 kg/cm2 and 14.3% and 10%,fine particle composition of soil mass was the minimum,the ability of the impact resistance damage was the strongest.For the same rainfall intensity,runoff was decreasing with abandon soil stockpiling time increasing,finally stabilize;in different rainfall condition,with abandon soil stockpiling time increasing,slope silt-laden rate presented volatility increases,slope sediment yield of total amount gradually reduced.