砾石覆盖条件下高寒区细沟侵蚀特征研究

丁宇浩　黄莎琳　王君惠　邓翔尹　万丹

摘 要：为了探究砾石覆盖条件下高寒土坡面细沟侵蚀特征，通过室内水槽模拟冲刷试验，研究不同坡度和流速条件下细沟侵蚀的特征。采用长为8 m的土槽，在4个流量和6个砾石覆盖度条件下进行冲刷试验研究，结果表明：砾石覆盖下细沟侵蚀的输沙率与砾石覆盖度呈先增后减的抛物线趋势;产流时间随着坡度的增加而减少;在相同流速与砾石覆盖度条件下，坡度越大，产流时间和产沙率越大，相应的产流量和产沙量也越大。

关键词：砾石覆盖;产流;产沙率

中图分类号：S157 文献标识码：A 文章编号：1003-5168（2021）26-0130-04

Study on Rill Erosion Characteristics in Alpine Region under Gravel Cover

DING Yuhao HUANG Shalin WANG Junhui DENG Xiangyin WAN Dan

（1.College of Resources and Environment， Tibet University of Agriculture and Animal Husbandry，Linzhi Tibet 860000;2.Tibet College of Agriculture and Animal Husbandry Research Center for Alpine Soil and Water Conservation，Linzhi Tibet 860000）

Abstract： In order to explore the rill erosion characteristics of gravel cover on alpine soil slopes， the characteristics of rill erosion under different slopes and velocities were studied through indoor flume simulation erosion tests. An 8 m long soil trough was used to carry out a scour test study under the conditions of 4 flows and 6 gravel coverage. The results showed that： the sand transport rate and gravel coverage of rill erosion under gravel coverage showed a parabolic trend of increasing first and then decreasing; the runoff time decreases as the slope increases; under the same flow velocity and gravel coverage conditions， the greater the slope， the greater the runoff time and sediment yield. The corresponding land flow and sediment yield are also greater.

Keywords： gravel cover;runoff;sand yield rate

砾石是基岩风化作用的产物，是土壤中粒径大于2 mm的矿物颗粒，在土壤中分布广泛[1]。我国北方土石山区褐土和西南地区紫色土中都有大量砾石存在[2-3]。青藏高原由于地质年轻化，结构破碎，基岩风化时间短，土层较薄，地表和土壤中存在大量大小不一的砾石。细沟侵蚀是土壤侵蚀中一种重要的形式，对坡面侵蚀产沙有重要作用。土壤中砾石的存在影响土壤侵蚀过程，因此认识砾石覆盖作用下的细沟侵蚀过程对西藏高寒区含砾石土壤细沟侵蚀的控制具有重要意义。JOMAA等[4]的研究表明，嵌入砾石可在一定程度上保护上壤方面免受雨滴击打，阻碍坡面径流的形成，降低坡面产沙能力。JOMAA等[5]的研究表明，砾石覆盖能有效降低高强度降雨对土壤的溅蚀。符素华等[6]的研究表明，土壤侵蚀量随砾石覆盖度增加呈负指数递减。……