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冰川冻土 ›› 2019, Vol. 41 ›› Issue (3): 615-628.doi: 10.7522/j.issn.1000-0240.2019.0401

• 寒区科学与技术 • 上一篇    下一篇

盐渍土与盐溶液冻结温度关系的试验研究

吴刚1,2, 邴慧1, 卜东升3   

  1. 1. 中国科学院 西北生态环境资源研究院 冻土工程国家重点试验室, 甘肃 兰州 730000;
    2. 中国科学院大学, 北京 100049;
    3. 新疆生产建设兵团 第一师农业科学研究所, 新疆 阿拉尔 843300
  • 收稿日期:2018-09-23 修回日期:2019-02-15 出版日期:2019-06-25 发布日期:2019-09-10
  • 通讯作者: 邴慧,E-mail:binghui@lzb.ac.cn. E-mail:binghui@lzb.ac.cn
  • 作者简介:吴刚(1993-),男,四川蓬安人,2016年在西南石油大学获学士学位,现为中国科学院西北生态环境资源研究院在读硕士研究生,从事寒区工程与冻土物理力学研究.E-mail:wugang@lzb.ac.cn
  • 基金资助:
    国家重点研发计划项目(2017YFC0504303);国家自然科学基金项目(41371090)资助

Experimental study on the relationship between saline soil and salt solution freezing temperature

WU Gang1,2, BING Hui1, BU Dongsheng3   

  1. 1. State Key Laboratory of Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China;
    2. University of Chinese Academy of Sciences, Beijing 100049, China;
    3. Institute of Agricultural Sciences of the First Division, The Xinjiang Production and Construction Corps, Aral 843300, Xinjiang, China
  • Received:2018-09-23 Revised:2019-02-15 Online:2019-06-25 Published:2019-09-10

摘要: 通过不同降温方式的冻结温度试验,明确了降温速率对土体冻结温度的影响,并采用快速降温方法,测定了不同含水率的三种天然氯(亚)盐渍土和黄土的冻结温度,以及不同浓度Na2SO4、NaCl溶液和由溶液配制的黄土的过冷温度和冻结温度,分析了降温速率、含水率、含盐量、盐类对土和溶液相变过程的影响。结果表明,快速降温得到的冻结温度值比缓慢降温得到的值偏低。当含水率低于盐渍土的塑限含水率时,水分是冻结温度的主要制约因素;当含水率大于土的塑限含水率时,天然盐渍土的含盐量对土的冻结温度起控制作用,Na2SO4含量控制含盐土的第一次相变,NaCl含量控制含盐土在低温下的第二次相变;低含盐量黄土含水率低于塑限含水率时,冻结温度随含水率增大而增大,但当含水率高于饱和含水率时,冻结温度随含水率变化不大。含Na2SO4的土和溶液的过冷温度变化规律与冻结温度变化规律类似,且其温度差值较小,通过Na2SO4溶液的冻结温度试验,可近似得到同浓度下含水率为16%只含Na2SO4黄土的冻结温度。

关键词: 盐渍土, 硫酸钠溶液, 二次相变, 冻结温度, 过冷温度

Abstract: In this paper, the effect of cooling rate on soil freezing temperature by freezing temperature tests are illustrated using different cooling methods. The freezing temperature obtained by rapid cooling is lower than that obtained by gradual cooling. Using the rapid cooling, the freezing temperature of some chlorine (sub) saline soils and loess with different water contents are gotten, so do the freezing temperature and supercooling temperature of solutions and loess with different Na2SO4 concentration, NaCl concentration. A series of influence factors, such as cooling rate, water content, salt content, salt type, have analyzed on the phase transition process of soil and solution. When the water content is lower than the plastic limit water content of the soil, the main limiting factor of natural chlorine (sub) saline soils freezing temperature is water content. When the water content is greater than the plastic limit water content of the soil, the salt content of natural saline soil is the main factor affecting soil freezing temperature. Among them, sodium sulfate controls the first phase change of the soil, and sodium chloride controls the second phase change of the soil. For loess with lower salinity, when the water content of soil is lower than the plastic limit water content, the freezing temperature increases with the increase of water content, but when the water content is higher than the saturated water content, the freezing temperature does not change much with water content. The change of supercooling temperature of soil and solution containing sodium sulfate is similar to that of freezing temperature, with small temperature difference. By the freezing temperature test of the Na2SO4 solution, the freezing temperature of only the sodium sulfate-containing loess having a water content of 16% at the same concentration can be obtained approximately.

Key words: saline soil, sodium sulfate solution, secondary phase transition, freezing temperature, supercooling temperature

中图分类号: 

  • P642.14