宁夏平罗盐碱地排水渠道稳定性影响因素分析

Influence Factors on the Drainage Channel Stability in the Pingluo Saline Land of Ningxia

以平罗西大滩实测土壤剖面为例,从渠道边界物质的粒度特征、粘土矿物含量及气候特征等方面,分析了排水渠道稳定性的影响因素。结果表明,研究区排水渠道的稳定性主要受到粒度结构的影响,其中上部泥质层的粘土矿物含量较高,其吸水膨胀和脱水收缩的交替变化可以导致渠道边界上层的疏松和坍塌;下部粉细砂层易于遭到流水的淘蚀,而冬春发生的冻融作用也会使该地层变得疏松,从而加剧了该地层在排水时的淘蚀作用。为了维护排水渠道的相对稳定性,渠道的边坡应尽量采用缓坡,同时需要在边坡上栽植根系茂密的矮小草本植物。

In this work the main influence factors on the drainage channel stability in the Pingluo Xidatan saline land were analyzed according to the changes of granularity and cay mineral content in the Xidatan columnar section and the local climate characteristics.Results showed that the drainage channel stability was mainly influenced by the granularity.At the upper stratum the clay mineral content is relatively higher.The expansion via hydration and constriction via dehydration of the clay mineral could induce the loosening and collapse of the upper stratum.At the lower stratum the preponderant silts and fine sands are prone to be eroded by the flow.Furthermore,the freezing and thawing in the lower stratum could enhance the erosion.For protection the drainage channel to avoid strong erosion the relative lower side slope of the drainage channel and insemination of runty grasses with thick root system in the drainage channel banks are needed.