赣北地区工程堆积体侵蚀水动力机理研究  

Hydrodynamic mechanism of engineering deposit erosion in Northern Jiangxi Province

作　　者：王雪松[1] 申卫博[1,2] 谢永生[1,2] 陈曦[3] 丁亚东[2] 马洪超[2] 

机构地区：[1]西北农林科技大学水土保持研究所,陕西杨凌712100 [2]中国科学院水利部水土保持研究所,陕西杨凌712100 [3]西北农林科技大学资源环境学院,陕西杨凌712100

出　　处：《水力发电学报》2015年第11期59-68,共10页Journal of Hydroelectric Engineering

基　　金：水利部公益性行业科研专项(201201048;201201047)

摘　　要：工程建设过程中形成的堆积体具有独特的土壤组成及特殊的堆积形态,堆积体表面土壤结构体缺失、土质松散、植物根系和有机质缺乏以及特殊的坡面构型等,导致其土壤侵蚀过程与传统坡面有着极大差异性。本研究采用人工降雨试验,设计10%、20%、30%三个砾石质量百分数和1.0 mm/min、1.5 mm/min、2.0 mm/min、2.5mm/min四个降雨强度,对坡顶平台有车碾压型工程堆积体薄层水流侵蚀动力学过程以及机理进行研究,结果表明:工程堆积体土壤剥蚀率是降雨强度和砾石质量百分数的二元线性方程(R2=0.919),可以根据堆积体的砾石质量百分数和所经历的降雨强度来预测土壤的剥蚀率。水流剪切应力、水流功率、单位水流功率和断面单位能与土壤剥蚀率均有一定相关性,水流功率是试验条件下用来描述堆积体土壤剥蚀率最好的水力参数,可以用水流功率来描述工程堆积体侵蚀动力过程。坡顶平台有车碾压型工程堆积体坡顶部的平台对堆积体侵蚀有一定的影响,通过分析发现平台对整个堆积体剥蚀率的贡献为5.0×10-6 kg/(m2·s),其大小与平台面积有关。Engineering deposits have unique soil constitutions and complex conditions of their surface layers that are quite different from those of a regular soil slope. Hydrodynamic mechanisms established through previous studies of the traditional slopes, are not applicable for such deposits with three- dimensional shapes and it is necessary to study the hydrodynamic process of soil erosion on the engineering deposits. In this study, we have conducted laboratory experiments of rainfall erosion on a special type of engineering deposits- roller compacted by construction machinery on the top platform of the slope, focusing on the hydrodynamic process of erosion in the conditions of four artificial rainfall intensities （1.0, 1.5, 2.0 and 2.5 mm/min） and three gravel contents （10%, 20% and 30%）. The results show that the soil detachment rate is a linear function of rainfall intensity and percentage gravel mass content with a squared correlation coefficient of R^2=0.919. Thus, the sediment yield can be predicted if these two parameters are known. Hydraulic parameters such as flow shear stress, stream power, unit stream power, and the specific energy of flow cross section, could also be used for calculation of the detachment rate. Among them, the stream power is the most suitable parameter and is highly correlated with the detachment rate （R2 = 0.884）. This indicates that the effect of water flow on the deposits tested in this study is better described in terms of its energy than its stress. A comparison reveals that for the deposits tested, both their top platform part and slope part contribute to the total detachment rate. The contribution by the former, which is 5.0×10^-6 kg/（m^2·s） for the experimental condition, depends primarily on the area of the top platform compacted.

关 键 词：土壤侵蚀 工程堆积体 水力学参数 

分 类 号：S157.1[农业科学—土壤学] S152.3[农业科学—农业基础科学]