治沟造地过程中水库诱发黄土盐渍化现象

Loess Salinization Phenomenon Induced by Reservoir in Process of Gully Land Consolidation

顾屯流域在治沟造地过程中共修建五座水库,水库蓄水后沟道地下水位抬升,表层黄土受强蒸发作用水分蒸发盐分析出累积逐渐形成盐渍化。通过现场调查、无人机、高密度电法和室内试验等方法探讨了顾屯流域黄土盐渍化成因及特征。研究表明,五号水库下游产生了盐渍化现象,黄土中可溶盐含量为2.2 g·kg^1。沟道内上游坡度是下游的两倍,五号水库液面高于下游并在大坝处产生了渗漏,物探结果中大坝上部高电阻下部低电阻现象与渗漏结果相符。水库渗漏影响盐渍化形成,使黄土中可溶盐含量增加电导率增大。ERT剖面结果表明渗漏影响深度约为18m,渗漏现象随距液面距离增加而减小,下游靠近大坝处黄土含水率及盐渍化程度更高。该研究对后续工程建设以及预防盐渍化产生具有积极意义。

During the process of gully land consolidation in the Gutun drainage area,five reservoirs were built.The groundwater level of the channel rises after the reservoirs are impounded,surface loess is subjected to strong evaporation,and salt accumulate for which forms salinization.The causes and characteristics of the salinization of loess in the Gutun valley were investigated by means of on-site investigation,drone,ERT and laboratory tests.The study shows that salinization occurs in the 5th reservoir,and the soluble salt content in the loess is 2.2 g·kg^-1.The upstream slope in the channel is twice as much as the downstream.The liquid level of the 5th reservoir is higher than that of the downstream and generates leakage at the dam.In the geophysical results,the low resistance of the dam is consistent with the leakage.Reservoir leakage affects the formation of salinization,which increases the soluble salt in loess and conductivity.The results of ERT profile show that the influence depth is about 18 m,the leakage phenomenon decreases with the increase of the distance from reservoir,and the moisture content and salinization degree of the loess are higher near the dam.This research has positive significance for the subsequent construction and prevention of salinization.