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Chinese Journal of Applied Ecology ›› 2020, Vol. 31 ›› Issue (5): 1587-1598.doi: 10.13287/j.1001-9332.202005.013

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Differences in hydraulic erosion processes of the earth and earth-rock Lou soil engineering accumulation in the Loess Region

JI Li-jing1, WANG Wen-long1,2*, KANG Hong-liang1, ZHAO Man1, GUO Ming-ming1, BAI Yun3, SU Huan1, NIE Hui-ying1   

  1. 1State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateaus, Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, Shaanxi, China;
    2Institute of Soil and Water Conservation, Chinese Academy of Sciences & Ministry of Water Resources, Yangling 712100, Shaanxi, China;
    3Key Laboratory of Ecological Rehabilitation of Northern Shaanxi Mining Area, Yulin University, Yulin 719000, Shaanxi, China
  • Received:2020-01-17 Online:2020-05-15 Published:2020-05-15
  • Contact: * E-mail: wlwang@nwsuaf.edu.cn
  • Supported by:
    This work was supported by the National Key Research & Development Program of China (2016YFC0501604) and the National Natural Science Foundation of China (41701316, 41761062, 40771127).

Abstract: An indoor rainfall simulation experiment was conducted to examine the hydrodynamic characteristics, erosion characteristics, and erosion dynamics mechanisms of earth (excluding gra-vel) and earth-rock (gravel mass fraction 30%) Lou soil engineering accumulation in the Loess area across different rainfall intensities and slope gradients. Results showed that the presence of gravel changed the hydrodynamic characteristics of the engineering accumulation slope. The flow velocity, froude number, unit stream power, and unit energy of water-carrying section of the earth-rock slope were 1.7%-49.7%, 6.7%-60.6%, 2.0%-44.6% and 1.0%-26.7% lower than those of the earth slope, while the Manning roughness coefficient and runoff shear stress of the earth-rock slope were 6.2%-169.4% and 5.7%-79.3% higher than those of the earth slope respectively. Under the intensity of 2.0 and 2.5 mm·min-1, erosion rate of the earth-rock slope was 26.2%-89.9% lower than that of earth slope. The gravel significantly reduced slope erosion of the Lou soil engineering accumulation. Erosion rate and hydrodynamic parameters of the two accumulations were linearly related. The erodibility parameters of earth-rock slope were 56.1%-73.3% lower than that of earth slope. In the critical hydrodynamic parameters, runoff shear stress of earth-rock slope was 11.1% higher, while the stream power, unit stream power and unit energy of water-carrying section were 25.4%, 64.0% and 5.0% lower than those of the earth slope, respectively. The existence of gravel controlled rainfall erosion process on the slope of the engineering accumulation to some extent.

Key words: Lou soil engineering accumulation, hydrodynamic characteristics, sediment characte-ristics, erosion dynamic mechanism