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为了研究砾石对工程堆积体降雨侵蚀规律的影响,采用室内人工模拟试验,以土质堆积体(砾石质量分数为0)为对照,研究了10%、20%和30%砾石质量分数堆积体边坡在模拟降雨条件下的径流水力特征、产沙过程及侵蚀动力机制。结果表明:1)产流0~6 min,砾石促进堆积体坡面细沟间径流流动;产流12~30 min后,砾石阻碍堆积体坡面细沟径流流动;2)含砾石堆积体坡面粗糙度增大,水流流态变缓,水流速度降低,且均以层流为主。较土质堆积体而言,30%砾石质量分数堆积体坡面阻力系数增大88.8%~288.4%,弗汝德数降低28.9%~41.8%,水流速度降低0~45.8%;3)径流含沙量随产流历时经历快速降低-平稳过渡-波动上升3个阶段,土质及10%砾石质量分数堆积体高含沙水流现象频发,且随雨强增大,重力坍塌次数增加,重力侵蚀程度增强。20%、30%砾石质量分数堆积体发生高含沙水流的几率约为0。相对土壤流失比与砾石质量分数呈极显著负指数函数关系;4)土壤剥蚀率与各侵蚀动力参数均可用简单线性函数关系描述,单位径流功率是描述风沙区土质和10%砾石质量分数工程堆积体侵蚀产沙的最优因子,径流功率是刻画20%、30%砾石质量分数工程堆积体土壤侵蚀参数更为合理的因子。结果可为全国范围工程堆积体土壤侵蚀模型的建立提供科学依据。
In order to study the effect of gravel on the rainfall erosion of the engineering deposit, indoor artificial simulation tests were conducted to compare the effects of gravel mass fraction (0%) on the slope of 10%, 20% and 30% Runoff hydraulic characteristics, sediment yield and erosion dynamics under simulated rainfall conditions. The results show that: 1) the flow rate is 0 ~ 6 min, the gravel can promote the runoff between the rafts in the slope of the pile body; after 12 ~ 30 min of runoff, the gravel impedes the flow of the runner on the slope of the pile body; 2) Roughness increases, water flow slows down, water flow rate decreases, and are mainly laminar flow. Compared with the soil mass, the slope resistance coefficient of 30% gravel mass accumulation body increased 88.8% -288.4%, the Froude number decreased 28.9% -41.8%, and the water velocity decreased by 0-45.8%. 3) The amount of sediment in the soil mass and 10% gravel mass fraction was high, and with the increase of rainfall intensity, the number of gravity collapse increased and the degree of gravity erosion increased . The probability of a 20% and 30% gravel mass accumulating body to produce a high sediment flow is about zero. The relative soil loss ratio and gravel mass fraction showed a very significant negative exponential function; 4) The soil erosion rate and each erosion power parameter could be described by a simple linear function. The unit runoff power was described as the soil quality in the wind-blown sand area and the 10% gravel mass fraction The optimum factor of body erosion and sediment yield and runoff power are more reasonable factors to describe the soil erosion parameters of the 20% and 30% gravel mass fraction. The results can provide a scientific basis for the establishment of a model of soil erosion in the whole area of China.