复合侵蚀作用下砒砂岩坡面侵蚀泥沙颗粒特征

Particle Characteristics of Erosion Sediment on Pisha Sandstone Slope Under Composite Erosion

明晰砒砂岩坡面侵蚀泥沙颗粒输移特征是研究黄河泥沙淤积问题的关键。采用水力、风力、冻融复合侵蚀实体模拟技术,研究在35°坡度和110 mm/h雨强条件下单一水蚀、冻融+水蚀、冻融+风蚀+水蚀3组不同侵蚀动力复合作用下,砒砂岩坡面侵蚀泥沙颗粒变化特征。结果表明:砒砂岩坡面在单一水蚀作用下以整体侵蚀为主,侵蚀泥沙颗粒变化稳定;冻融+水蚀作用下粗颗粒产出明显,冻融作用对粗颗粒的影响凸显;冻融+风蚀+水蚀作用下坡面稳定性最差,侵蚀泥沙颗粒变化最剧烈。复合侵蚀作用下坡面侵蚀过程以搬运粒径较大的泥沙颗粒为主;各粒级侵蚀泥沙颗粒随侵蚀动力的增加起伏变化剧烈。

The key to study the sediment deposition of the Yellow River is to clarify the sediment transport characteristics of the erosion sediment on the Pisha Sandstone slope.The physical simulation technology of water,wind and freezing-thawing composite erosion was used to study the variation characteristics of erosion sediment particles on Pisha Sandstone slope under the composited action of three groups of different erosion dynamics,which were single water erosion,freezing-thawing water erosion,and freezing-thawing wind water erosion,under the condition of 35°slope and 110 mm/h rain intensity.The results showed that the Pisha sandstone slope was dominated by overall erosion under single water erosion action,and the erosion sediment particles changed stably.Under the action of freezing-thawing water erosion,coarse particles were produced obviously,and the effect of freezing-thawing on coarse particles was prominent.The slope stability was the worst under freezing-thawing wind water erosion,and the change of erosion sediment particles was the most drastic.In the process of slope erosion under composite erosion,sediment particles with larger diameter were mainly transported.The fluctuation of erosion sediment particles with the increase of erosion dynamics changed dramatically.