黄土高原淤地坝坝地淤积物两个重要物理特性指标研究

Two Key Physical Characteristics Indexes of Farmland Sediment for Check Dams in Loess Plateau

淤地坝淤积过程机理的研究是个薄弱环节，坝地淤积物的主要物理特性指标的研究能为淤积过程机理的研究提供重要依据。在调查典型淤地坝挖取剖面采集土样的基础上，通过室外试验与室内分析计算相结合的方法，研究了坝地各层淤积物的干容重和粒径级配两个物理特性。结果表明：淤积程度相似（淤积年限相近．淤积层数相当），淤积物的干容重的变化规律类似；对于同一座坝，淤积层厚度相近的各个淤积层，其干容重从上到下有增大的趋势；坝地各层淤积物的粒径主要集中在0．025～0．1mm之间。该结果可为进一步求解淤积沙量，建立各淤积层淤积量与次侵蚀性降雨的相关关系提供重要参数。

Depositing process mechanics is the unsubstantial part, study on physical characteristics indexes of farmland sediment for check dam is very important for depositing process mechanics. Based on the data from field investigation of typical check dams, by combining outdoor experiments with indoor experiments, the sediment physical characteristics indexes of farmland sediment was researched. The ＇result indicates that dry bulk density variation rule is simulated while depositing degree resembles; for the same check dam, the dry bulk density has a increasing tendency from upper layer to bottom layer while the thickness of depositing layer resembles; the grain diameter was mainly distributed among the range from 0. 025 mm to 0.1 ram. The results were useful for providing important parameters for solving depositing sediment and building the co-relationship between the sediment amount of the sedimentation layer and the precipitation.