沙棘柔性坝对砒砂岩沟道泥沙粒径分布及有机质影响

Effects of Seabuckthorn Flexible Dam on Sediment Particle Size Distribution and Organic Matter in the Soft Sandstone Gully

为了进一步研究沙棘"柔性坝"对砒砂岩沟道泥沙的影响,基于内蒙古砒砂岩地区沙棘"柔性坝"野外试验,根据单座沙棘"柔性坝"一次降雨淤积后的试验数据,运用对比分析的方法,研究了沙棘"柔性坝"对砒砂岩沟道泥沙粒径分布及有机质的影响及其拦沙效果。结果表明:单座沙棘"柔性坝"能够提高砒砂岩沟道泥沙有机质含量,具有淤粗排细的分选功能和良好的拦沙效果。泥沙有机质从沙棘"柔性坝"上游到下游逐渐增加,沿泥沙剖面表现出先增后减的趋势;泥沙粒径从沟道上游到下游先增大后减小,沿一次降雨淤积的泥沙剖面也表现出先增后减的趋势;暴雨后沙棘"柔性坝"单位面积淤积泥沙的平均厚度为0.369m,与对比沟相比,淤积的泥沙厚度明显较高。

In order to study the effects of the seabuckthorn flexible dam on sediment in the soft s and stone gully,field experiments were carried out in the soft rock region of Inner Mongolia, and based on the experimental data of single seabuckthorn flexible dam after a rainstorm,effects of seabuckthorn flexible dam on sediment particle size distribution and organic matter, and sediment retention effect of the dam were analyzed through employing the method of comparison.Results showed that single seabuckthorn flexible dam improved the organic matter content of gully sediment, and it had silt separation and fine sorting function and good sediment retention effect.The content of sediment organic matter increased from upstream to downstream of the seabuckthorn flexible dam, and the content of organic matter in middle sediment layer was higher than those in surface and bottom layer.The sediment particle size increased first and then decreased from upstream to downstream of the gully, and the same tendency appeared along the sediment profile of a rainfall deposit.After a rainstorm,the average thickness of silt deposited in unit area of seabuckthorn flexible dam was 0.369 m, and it was significantly higher than that of the control group.