Influence of Soil Configuration on the Morphology of the Rill Development in Granitic Red Soil
In order to investigate the reasons for the special variation in the fine furrow morphology of the granitic red soil the rill and to explain how soil configuration influences the development of the rill morphology.we designed three soil configurations(H,S,and HS)with different runoff rates.Three soil configurations,namely,a singlered soil layer(H),single sandy soil layer(S)and upper red and lower sandy laminated soil layer(HS),were designed to simulate indoor fine furrow scouring experiments with different runoff rates(low runoff rate 3 L/min,high runoff rate 6 L/min)and different slopes(medium slope 20°,steep slope 40°).The results showed that:under the H treatment,the gully morphology developed more towards"V"and"U";under the S treatment,the gully formed a deep and wide trapezoidal cross-section with a narrow top and a wide bottom for a short period of time during the process of the rill development,and then collapsed;under the HS treatment,the gully morphology was able to develop into a trapezoidal section and could continue to expand and develop.Compared with H and S,21 gully bank failures occurred in the HS steep slope(40°)treatment,of which 63%had single failures of>1 kg.The HS steep slope(40°)treatment had more frequent gully bank failures.The fluctuations of Re and Fr were more drastic than those in the H and S treatments,which is more favourable to the formation of trapezoidal sections.the upper red layer of HS had the lowest water content of 0.31 cm3/cm3 and the highest shear strength of 178 kPa at the time of HS the rill collapse compared to H and S.The lower sand soil layer of HS had a higher water content of 0.33 cm3/cm3 and the lowest shear strength of 54 kPa.The soil configuration of upper red and lower sandy laminated soil layer was the niche the ephemercil gully where the rill morphology of the granitic red soil rill developed into an upper-narrower and lower-deeper and wider trapezoidal profile steep slopes and high runoff volume are more favourable to the formation and development of specific patterns in the rill,and the niche furrows are the initial stage of the development of the Benggang.The results could provide a theoretical basis for the prevention and control of the initial development of the Benggang.
laboratory scour experimentrillthe niche like ephemeral gullysoil structurebank collapse
国家科技期刊平台
NSTL
万方数据
维普
