吉林省西部湖泊地带苏打盐渍土溶陷性

吉林省西部苏打盐渍土的溶陷性是该地区河湖连通工程无衬砌渠道的主要工程问题之一，研究苏打盐渍土溶陷特性可为渠道溶陷防治提供依据。以乾安县内湖泊规划渠道经过的盐渍土区为研究对象，通过原状土的室内溶陷试验，得到了苏打盐渍土溶陷系数随压力变化的规律，分析了深度150 cm以上土壤溶陷系数随深度变化的关系。结果表明：苏打盐渍土在200 kPa的压力下，首次遇水时产生最大的溶陷变形量，溶陷系数最大，溶陷性最强，随着压力增大，溶陷系数降低；深度30 cm以上和120 cm以下的土壤不具溶陷性，30~120 cm的苏打盐渍土具有轻微溶陷性；30 cm以上的土壤作为积盐层，高浓度的交换性Na⁺使得土壤颗粒聚结，孔隙比较低，土壤水分入渗受阻，渗流作用微弱，盐分不易溶解、流失；30~120 cm的土壤间理化性质的差异是造成盐渍土溶陷的原因之一，是渠道溶陷治理的关键区域。

Salt Resolving Slump of Sodic Saline Soil in the Lake Area of Western Jilin Province

The salt resolving slump characteristics of sodic saline soil in the western part of Jilin Province are the main engineering problem of lining-free channels in the connectivity of rivers and lakes in the region. This study of salt resolving slump characteristics of sodic saline soil can provide the basis for problem solving. By taking the saline soil area passing through a planning channel in Qian’an as the research object, through the indoor dissolution test on undisturbed soil, the variation law of the salt resolving slump coefficient of sodic saline soil with the pressure load and the relationship between the salt resolving slump coefficient and the soil above 150 cm were obtained. The results are as follows: Under the pressure of 200 kPa, sodic soil produced the largest amount of slump deformation when it first encountered water, and the salt resolving slump coefficient was the largest; with the pressure increased, the salt resolving slump coefficient decreased. The soil with a depth of less than 30 cm and more than 120 cm was not collapsible, and the sodic saline soil with a depth of 30-120 cm was slightly collapsible. The soil with a depth of 30 cm or more acted as a salt accumulation layer, the high concentration of exchangeable sodium made the soil particles coalesced, the void ratio low, the soil moisture infiltration blocked, the seepage effect weak, and the salt not easy to dissolve and lose. The sodic saline soil with a depth of 30-120 cm had slight disintegration. The difference of physical and chemical properties between the upper and lower layers is one of the causes of the slump of saline soil, which is also the key area of channel regulation.