坝地淤积物干容重分布规律及其在层泥沙还原中的应用

针对淤地坝减水减沙效益计算中以1.35 g/cm3作为转换值求层泥沙淤积量时存在较大差异的问题,选取典型坝挖取剖面进行剖面分析,并提取每层淤积物的土样进行土样干容重测定,分析了典型坝坝地淤积物的干容重分布情况。结果表明,对同一座典型坝,其坝地淤积物的干容重值并不是沿深度方向保持不变,而是沿纵向有一定的波动趋势,但波动幅度不大;对于淤积程度相似的典型坝,其干容重值接近,干容重变化幅度类似;以实测每层淤积物干容重还原层泥沙淤积量,可以较精确地对应层淤积量与次侵蚀性降雨,以此对淤积过程机理进行分析将更加科学合理。

Distribution law of deposits dry bulk density and its application in sediment restoration of check-dam

In view of the problem of differences resulted from the application of conversion parameter of 1.35 g/cm^3 to the benefit calculation of soil and water conservation for check dams,this study chose typical check dams ,excavated the sections of the dams ,analyzed section condition, collected soil samples of each layer, determined the dry bulk density of samples, analyzed the dry density distribution condition of the dams and restored the layer sedimentation amount of the dams. Results show that to the same check dam, the dry bulk density of each layer is not equal in depth,but has a fluctuating tendency along longitudinal direction with a small fluctuation margin;to the two typical check dams with similar depositing degree,the value and the variation amplitude of dry bulk density are resembled ;and the presented method can restore the amount of the sedimentation and make the layer sediment yields correspond to the erosive rain more accurately,which offers a scientific and rational tool to depositing process analysis.