关键词: 物质组成, 水系, 产沙, 非线性, 实验

Abstract: In this paper an experimental study on influence of materiel component to non linear relation between sediment yield and drainage network development has been completed in the Lab of Fluvial Geomorphology in the Institute of Geography, Chinese Academy of Sciences. The area of flume drainage system is 81 2 m², the longitudinal gradient and cross section slope are from 0 0348 to 0 0775 and from 0 0115 to 0 038, respectively. Different model materials with a medium diameter of 0 021 mm, 0 076 mm and 0 066 mm cover three experiments for each. At the beginning the ψ shaped small network is dug in the flume, an artificial rainfall equipment is a sprinkler system composed of 7 downward nozzles, distributed by hexagon type and a given rainfall intensity is 35 56 mm/hr·cm². Three experiments are designed by process response principle. Running time spans are 720 minutes, 1 440 minutes and 540 minutes for Run Ⅳ, Ⅵ, and Ⅰ respectively.\;Three experiments show that the sediment yield processes are characterized by delaying with a vibration. During network development the energy of a drainage system is dissipated by two ways, of which one is increasing numbers of channel (rill and gully), and another one is enlarging the channel length. The fractal dimension of a drainage network is exactly an index of energy dissipation of a drainage morphological system. Change of this index with time is a unsymmetrical concave curve. Contracting three experiments explains that the vibration and the delaying ratio of sediment yield processes increase with material carousing, while the number of channel decrease. The length of channel enlarges with material fining. There exists non linear relationship between fractal dimension and sediment yield with an unsymmetrical hyperbolic curve. The absolute value of delaying ratio of the curve reduces with time running and material fining. It is characterized by substitution of situation to time.

Key words: material component, network, sediment yield, nonlinear relation, experiment