• 论文 •

侵蚀基准面下降对水系发育与产沙影响的实验研究

1. 中国科学院地理科学与资源研究所, 北京 100101
• 收稿日期:2003-01-14 修回日期:2003-05-28 发布日期:2011-02-25
• 作者简介:金德生(1940-),男,江苏江阴人,研究员。主要从事流水地貌研究及实验模拟,发表论文60余篇, 编著4本。E-mail:jinds@igsnrr.ac.cn
• 基金资助:

国家自然科学基金委员会;水利部联合资助国家自然科学重大基金资助项目(59890200);国家自然科学青年基金项目(40201008)

Influence of base level lowering on sediment yield and drainage network development:an experimental analysis

JIN De sheng, ZHANG Ou yang, CHEN Hao, GUO Qing wu

1. Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China
• Received:2003-01-14 Revised:2003-05-28 Published:2011-02-25

Abstract:

In this paper an experimental study on influence of base level lowering on non linear relationship between sediment yield and drainage network development has been completed in the Lab of Fluvial Geomorphology in the Institute of Geographic Sciences and Natural Resources Research,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 Three experiments are a background drainage development (Run I) and drainage developments influenced by the first (Run II) and second (Run III) base level lowering, respectively They are covered by the same model materials with a medium diameter of 0.021 mm At the beginning of each experiment the (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 span for each experiment is 720 minutes The background experiment shows that the sediment yield process is characterized by delaying with a vibration During network development the energy of a drainage system is dissipated by two ways, of which one is to increase the numbers of channels (rill and gully),and the other one is to enlarge the channel length As the first base level lowering occurs the channel at the model drainage outlet is down cut and enlarged and the sediment yield process appears a complex response with double peaks at first and then decreases When the second base level lowering occurs the phenomena was duplicated, but the influence of the second base level lowering on intensity and amplitude is smaller than that of the first base level lowering 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 an unsymmetrical concave curve Comparative result of the three experiments explains that the influence of base level lowering is reducing with the elapse of time and far away from the outlet of model drainage basin

PACS:

• P931.1