Characteristics of Runoff and Sediment Yield on Loose Red Soil Accumulation Slope under Gravel Action
This study aims to explore the runoff and sediment yield characteristics on loose engineering accumula-tions under different rainfall conditions.Based on field investigations,we developed models of accumulation test tanks for simulated rainfall experiments to examine the runoff and sediment yield disparities between pure accumula-tion and accumulation with 20%gravel content under varied rainfall conditions.The findings revealed the following:1)Gravel effectively delayed runoff initiation on accumulation slopes,exhibiting an average delay benefit of 299.56%.Throughout the rainfall process,both pure and mixed soil and gravel accumulations demonstrated a simi-lar increasing trend in runoff rate with prolonged runoff generation duration.The average runoff rate escalated by 34.48%-244.83%with rising rainfall intensity.In comparison to pure accumulation,mixed soil and gravel accumu-lation displayed a decrease in average runoff rate by 6.54%-45.83%,along with a reduction in average flow veloci-ty by 13.76%-30.54%.2)The erosion rate of both pure and mixed soil and gravel accumulations generally exhibi-ted a gradual increase or tended to stabilize with runoff generation duration under rainfall intensities below 1.5 mm/min.The average erosion rate of mixed soil and gravel accumulation was 80.39%-84.95%lower than that of pure accumulation.However,under heavy rainfall conditions(2.0 mm/min),the erosion rate of pure soil accumulation experienced rapid escalation followed by a decline,while that of mixed soil and gravel accumulation increased in a fluctuating manner,with the average erosion rate 20.04%higher than the former.3)Both rainfall intensity and gravel content significantly influenced runoff,sediment yield,and flow velocity on accumulation slopes,indicating notable differences overall(P<0.05).The overall trend displayed an increase in both water and sediment.These results offer scientific guidance for implementing measures against soil erosion in production and construction pro-jects involving accumulations,and provide fundamental data for establishing soil erosion prediction models for accu-mulation engineering.
red soil accumulationsimulated rainfallrunoff and sediment yieldrunoff velocitymixed soil and gravel