兰州大学机构库 >土木工程与力学学院
固化硫酸盐渍土水盐迁移试验研究
Alternative TitleExperimental Study on Water and Salt Migration of Solidified Sulphate Saline Soil
常承睿
Thesis Advisor吕擎峰
2017-06-01
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name硕士
Keyword硫酸盐渍土 地聚物胶凝材料 毛细输送机制 水盐迁移 盐胀
Abstract

我国西北地区特殊的自然环境条件,使得该地区存在大量的硫酸盐渍土。硫酸盐渍土含有大量的阴阳离子,并且是一种多孔介质材料。在强烈的蒸发作用下,盐渍土土体下的地下水会通过土体中的孔隙向上运动,并带动地下水和土体内的盐分向上迁移,使盐分积聚在土体上部,破坏工程建筑设施。本文选取甘肃玉门的硫酸盐渍土为研究对象,制作压实盐渍土和地聚物胶凝材料固化盐渍土,分别以蒸馏水和模拟玉门地下水的复合盐溶液作为迁移溶液,在室内常温常压条件下,进行压实和固化盐渍土土柱(h=10cm)顶部开放条件下的水盐迁移试验。对比分析土样在不同时间梯度和位置的含水率、含盐量和电导率变化规律,揭示固化剂对不同离子迁移的影响。本文得到如下的结论:  

(1)压实土在蒸馏水迁移溶液条件下的毛细水迁移速率最大;固化土的毛细水迁移速率最小,而且迁移溶液对其影响很小,说明固化盐渍土有减缓毛细水上升的作用。毛细水迁移稳定后,压实土土柱上部含水率小于下部,沿高度近似线性分布;固化土土柱上部含水率大于下部,沿高度先线性增大后保持不变,说明固化盐渍土具有明显的稳定持水作用。

(2)固化土中Cl-、SO42-和Na+的迁移速率明显小于压实土中的迁移速率,说明固化盐渍土有较好的阻碍盐分迁移的作用。

(3)由于盐分迁移和表面蒸发作用,水盐迁移稳定后,整体上土柱下部离子浓度降低,顶部离子浓度升高,离子在顶部发生积聚;固化土土柱顶部离子含量明显小于压实土。

(4)电导率的分布与离子含量的分布高度相关,最终呈现出土样下部电导率较低、上部电导率较高的规律。

Other Abstract

The special natural environment makes a great amount of sulfuric saline soil in the northwest of China. Sulfate soil is a porous media material and contains a large number of anions and cations. Under the strong evaporation, the groundwater under the saline soil will move up through the voids in the soil and the salt migrates in the soil, so the salt would accumulate in the upper part of the soil and destroy the buildings and facilities. In this paper, the saline soil of Yumen in Gansu Province was selected as the object of the research. The compacted saline soil and the saline soil reinforced by geopolymer are made into specimens. The distilled water and compound salt solution simulated the groundwater of Yumen were used as the migration solution. At normal temperature and pressure, the water and salt migration test was carried out for compaction and solidification of salted soil column (h = 10cm) with an open top. The changes of water content, salt content and electrical conductivity of soil samples at the different time gradients and heights were compared and the effects of curing agents on different ion transport were revealed. The article gets conclusions as follows.

(1)When the transport solution is distilled water, the capillary water migration rate of the compacted soil is the maximum. The capillary water migration rate of the solidified soil is the minimum and the different migration solutions have little effect on migration rate, which indicates that the solidified saline soil has the effect of slowing the rising of the capillary water. When the capillary water is stable, the water content of the upper part of the compacted soil is less than that of the lower part, which shows the approximate linear distribution along the height. While the water content of the solidified soil column in the upper part is larger than that of the lower part which increases at first and then keeps constant along the height, which indicates that the solidified saline soil has significantly stable water holding effect.

 (2)The migration rate of Cl-, SO42- and Na+ in the solidified soil is significantly smaller than that in the compacted soil, which indicates that the solidified saline soil has a significant hindrance effect on the salt migration.

 (3) Due to the salt migration and surface evaporation, the concentration of ions in the lower part of the soil column decreases and the ion concentration increases at the top of the soil column. When the transfer of water and salt is stable and the ion accumulates at the top, the ion content in the top of solidified soil column was significantly smaller than that of the compacted soil.

(4) The distribution of the conductivity is highly correlated with the distribution of the ion content, and finally it shows that the lower conductivity in the lower part of the soil sample and the higher conductivity in the upper part of the soil sample.

URL查看原文
Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/226394
Collection土木工程与力学学院
Recommended Citation
GB/T 7714
常承睿. 固化硫酸盐渍土水盐迁移试验研究[D]. 兰州. 兰州大学,2017.
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