黄土台塬区红土崩解特性对泻溜侵蚀的影响  

Effect of Lateritic Soil Disintegration Properties on Slumping Erosion in Loess Tableland Area

作　　者：李哲[1] 王健[1] 蔡泽康 封瑞坤 李锋 卜芳俠 王晓冲 Li Zhe;Wang Jian;Cai Zekang;Feng Ruikun;Li Feng;Bu Fangxia;Wang Xiaochong(College of Soil and Water Conservation Science and Engineering,Northwest Agriculture and Forestry University,Yangling,Shaanxi 712100,China;Yan’an Soil and Water Conservation Monitoring Sub-station,Yan’an,Shaanxi 716000,China;Hancheng District Soil and Water Conservation Workstation,Hancheng,Shaanxi 714000,China)

机构地区：[1]西北农林科技大学水土保持科学与工程学院,陕西杨凌712100 [2]延安市水土保持监测分站,陕西延安716000 [3]韩城市水土保持工作站,陕西韩城714000

出　　处：《水土保持通报》2024年第5期1-9,57,共10页Bulletin of Soil and Water Conservation

基　　金：国家自然科学基金项目“半干旱区物理结皮对土壤CO_(2)释放的阻滞效用及机制”(42377332);“十四五”国家重点研发计划子课题“风水复合侵蚀动力学模拟与产输沙预测”(2022YFF130080105)。

摘　　要：[目的]探析红土崩解特性和泻溜侵蚀发生的关系,为坡面治理提供理论依据。[方法]测量泻溜边坡坡度、坡积体休止角等基本参数,试验测定红土团聚体特性及干湿交替条件下崩解过程,分析泻溜侵蚀地区发生泻溜侵蚀的边坡条件、红土水稳性团聚体稳定性和崩解特性的变化情况。[结果]①边坡坡度和休止角是泻溜侵蚀发生的控制性因素之一。黄土台塬区泻溜边坡坡度40°以内很少发生泻溜,大于80°大大减弱。红土与泻溜坡积体自然休止角范围为25°~36°。②红土团聚体绝大部分为非水稳性团聚体,团聚体稳定性差,因此遇水极易崩解从而造成泻溜侵蚀的发生。红土团聚体干筛平均质量直径MWD与几何平均直径GMD分别为2.16 mm,1.37 mm,湿筛平均质量直径MWD与几何平均直径GMD分别为0.51 mm,0.25 mm,团聚体破坏率PAD为57.66%,分形维数D为2.96,ASI是转移矩阵法中表示团聚体总体稳定性的参数,红土ASI为1.75。③干湿交替通过减小红土崩解程度从而减弱泻溜侵蚀的发生。自然状态条件下红土崩解程度最大,最大崩解指数为81.79%,平均崩解速率为51.03 g/min;干湿交替条件下红土崩解程度较自然状态减小;不同干湿交替条件之间红土最大崩解指数不同但差异性不显著。④红土平均崩解速率与泻溜坡积体休止角、泻溜边坡坡度与ASI呈极显著正相关关系(p<0.01)。[结论]红土崩解特性与泻溜侵蚀的发生有密切联系,干湿交替通过减小红土崩解程度从而减弱泻溜侵蚀的发生。[Objective]The relationship between laterite disintegration characteristics and the occurrence of slumping erosion was investigated in order to provide a theoretical basis for slope management.[Methods]The basic parameters of slumping slopes such as slope gradient and angle of repose were measured;the characteristics of laterite agglomerates and the disintegration process under alternating wet and dry conditions were experimentally determined;and the conditions of the slope,stability of laterite water-stable agglomerates,and changes of the disintegration characteristics of the slumping erosion area were analyzed.[Results]①Slope gradient and angle of repose were two factors that influenced the occurrence of slumping erosion.Sloughing was unusual in loess plateau areas with slope gradients of 40°or less and was considerably weakened by gradients greater than 80°.The natural angle of repose between red soil and slumping slopes varied from 25°to 36°.②Most of the laterite agglomerates easily disintegrated when exposed to water because they were non-hydrostable and had weak stability,resulting in sloughing and erosion.The average mass diameter(MWD)and geometric mean diameter(GMD)of the laterite agglomerates were 2.16 mm and 1.37 mm for dry sieve and 0.51 mm and 0.25 mm for wet sieve,respectively.The percentage of agglomerate destruction(PAD)was 57.66%,with a fractal size D of 2.96.aggregate stability index(ASI)is a metric that represents the overall stability of agglomeration in the transfer matrix method,and the red clay ASI in this study was 1.75.③Dry-wet alternation reduced the rate of slumping erosion by reducing laterite disintegration.The highest disintegration index was 81.79%,and the average disintegration rate was 51.03 g/min.The disintegration degree of the laterite was lowered under the dry-wet alternation condition compared to under the natural state.The maximum disintegration index of the laterite varied between different dry-wet alternation circumstances but the difference was not statistically

关 键 词：红土 泻溜 休止角 团聚体 土壤崩解性 

分 类 号：S157.1[农业科学—土壤学]