Hydraulic Characteristics and Sediment Yielding on Engineering Excavated Soil Slope under Simulated Rainfall

Xi Li, Chongqing Wang, Shixiong Jiang, Sunxian Weng, Yanhong Che, Yao Chen

2021

Abstract

Engineering excavated soil slopes play an important role in artificial soil loss. In order to assess the impact of these engineering excavated soil slopes, hydraulic characteristics and sediment generation must be quantified. Field rainfall simulation experiments were conducted under five rainfall intensities (0.6, 1.1, 1.61, 2.12 and 2.54 mm/min) and three slope gradients (10°, 15°and 20°) on engineering excavated soil slopes. The precipitation of each rainfall was set to 50 mm, the duration of rainfall was 83, 45, 31, 24 and 20 min for simulated rainfall intensities of 0.6, 1.1, 1.61, 2.12 and 2.54 mm/min respectively. Plots used in this study were laid out to be 3 m in length and 1 m in width. Calibration of rainfall intensities was conducted before each experiment. Totally, 45 simulated rainfall events were performed. Three indices were used to research the soil erosion processes, including surface and subsurface runoff volume and the sediment yield. Results showed that: 1) both surface and subsurface runoff varied depending on slope gradient and rainfall intensity. Surface runoff and subsurface runoff were 33.6~42.7 mm and 0.15~ 1.24 mm, respectively. The process of surface runoff yield was the main hydrological process, accounting for 67.2~85.4% of the precipitation. Under conditions of low (0.6 mm/min) and high (2.12 and 2.54 mm/min) rainfall intensity, surface runoff increased with slope. 2)The averaged flow velocity, Reynold number, Froude number, Darcy-Weisbach friction coefficient, Manning roughness coefficients and stream power were 0.047~0.104 m/s, 48.985~392.918, 0.355~0.581, 1.317~5.171, 0.044~0.101 m-1/3·s, 0.029~0.457 kg·s-3, respectively. In addition, flow velocity and Reynold number had a greatly significant correlation with rainfall intensities, Manning roughness coefficients, Darcy-Weisbach friction coefficients and stream power a week correlation with rainfall intensity, Froude number had a week correlation with rainfall and slope. There was no obvious relationship between Darcy-Weisbach friction coefficient and the Reynolds number and there was a “increase resistance” phenomenon in engineering excavated soil slopes. 3) Interrill erosion was the main erosion form on engineering excavated soil slopes. Rainfall intensity, runoff rate and slope gradient are key factors to model sediment yield rate. Three commonly interrill erosion models were evaluated and compared, the fitness of model followed the pattern: model 1(NSE=0.977)>model 2(NSE=0.966)>model 3(NSE=0.924). A further comparison between the models showed that the convex curvilinear slope factor (model 1) was more precise than the power (model 3) and linear (model 3) slope factor in describing the effect of slope gradient for this data. Interrill erodibility adopted in the WEPP model was determined as 0.332×106 kg·s·m-4. The results provide valuable data for establishing water erosion prediction model of engineering excavated slope.

Paper Citation

in Harvard Style

Li X., Wang C., Jiang S., Weng S., Che Y. and Chen Y. (2021). Hydraulic Characteristics and Sediment Yielding on Engineering Excavated Soil Slope under Simulated Rainfall. In Proceedings of the 7th International Conference on Water Resource and Environment - Volume 1: WRE, ISBN 978-989-758-560-9, pages 458-466

in Bibtex Style

@conference{wre21,
author={Xi Li and Chongqing Wang and Shixiong Jiang and Sunxian Weng and Yanhong Che and Yao Chen},
title={Hydraulic Characteristics and Sediment Yielding on Engineering Excavated Soil Slope under Simulated Rainfall},
booktitle={Proceedings of the 7th International Conference on Water Resource and Environment - Volume 1: WRE,},
year={2021},
pages={458-466},
publisher={SciTePress},
organization={INSTICC},
doi={},
isbn={978-989-758-560-9},
}

in EndNote Style

TY - CONF

JO - Proceedings of the 7th International Conference on Water Resource and Environment - Volume 1: WRE,
TI - Hydraulic Characteristics and Sediment Yielding on Engineering Excavated Soil Slope under Simulated Rainfall
SN - 978-989-758-560-9
AU - Li X.
AU - Wang C.
AU - Jiang S.
AU - Weng S.
AU - Che Y.
AU - Chen Y.
PY - 2021
SP - 458
EP - 466
DO -