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干旱区地理 ›› 2017, Vol. 40 ›› Issue (1): 131-137.

• 生物与土壤 • 上一篇    下一篇

低干密度盐渍细砂土低温特性试验研究

潘高峰1, 吴亚平1, 刘振1,2, 张晓波1, 李君玉1,3, 陈鄂1,4, 周勇5   

  1. 1 兰州交通大学 土木工程学院, 甘肃 兰州 730070;
    2 江苏省建筑工程质量检测中心有限公司, 江苏 南京 210028;
    3 内蒙古交通设计研究院有限责任公司, 内蒙古 呼和浩特 010000;
    4 山西省交通规划勘察设计院, 山西 太原 030012;
    5 青海省地方铁路建设投资有限公司, 青海 西宁 810000
  • 收稿日期:2016-09-15 修回日期:2016-12-03 出版日期:2017-01-25
  • 通讯作者: 吴亚平.Email:wypsw@163.com
  • 作者简介:潘高峰(1990-),男,四川达州人,硕士研究生,主要从事路基工程灾害防治方面研究.Email:pgfeng717@163.com
  • 基金资助:

    中国铁路总公司科技研究开发计划课题(2015G005-C);国家科技支撑计划课题(2014BAG05B05)

Experimental study on low temperature properties of dry density salted fine sand

PAN Gao-feng1, WU Ya-ping1, LIU Zhen1,2, ZHANG Xiao-bo1, LI Jun-yu1,3, CHEN E1,4, ZHOU Yong5   

  1. 1 School of Civil Engineering, Lanzhou Jiaotong University, Lanzhou 730070, Gansu, China;
    2 Jiangsu Testing Center for Quality of Construction Engineering Co., Ltd., Nanjing 210028, Jiangsu, China;
    3 Inner Mongolia Transit Design and Research Institute Co., Ltd., Hohhot 010000, China;
    4 Traffic Planning Surveying & Designing Institute of Shanxi Province, Taiyuan 030012, Shanxi, China;
    5 Qinghai Local Railway Construction Investment Co., Ltd., Xining 810000, Qinghai, China
  • Received:2016-09-15 Revised:2016-12-03 Online:2017-01-25

摘要: 利用2015年9月采自青海北霍布逊湖区的原土样,自行配比进行了室内盐渍细砂土冻胀试验,研究了低干密度盐渍细砂土的低温特性变化规律,探讨了盐渍细砂土的冻胀机理,集中分析了土的冻缩特性。研究发现低干密度盐渍细砂土在不同含水率条件下土的冻胀规律差异很大。低含水率条件下会有冻缩现象,高含水率条件下只会有冻胀现象,临界含水率(含水率14%)条件下细砂土先出现冻缩,之后随着温度的降低又出现冻胀,且由于温度引起的体积变化均在-28℃~-30℃时达到稳定;土的冻缩随着含盐量增加先呈递增趋势,后又呈递减趋势,在中间含盐量10%达到最大;除临界含水率条件下,盐渍细砂土的冻胀、冻缩均与温度呈三次多项式关系,与含水率呈线性关系。研究结果能够为盐渍土地区的工程建设提供有价值的理论依据。

关键词: 盐渍细砂土, 冻胀规律, 温度, 含水率, 含盐量

Abstract: Hobson Lake as North Qinghai Province is one of China's most serious soil salinization hazard areas. In recent years, with the rapid development of economy and technology, more and more construction projects will be carried out here. In order to ensure long-term stability and security of the buildings in the area, a scientific inquiry of engineering properties and mechanical properties of saline soil is necessary. Based on the natural accumulated salt and local soil collected from Hobson Lake in September 2015, the indoor frost heave experiment of salted fine sand was performed to study the low temperature characteristics of salted fine sand with low dry density, investigate the mechanism of frost heave of salted fine sand, and analyze the frost shrinkage properties of salted fine sand. Results show as follows: (1)Salted fine sandy with low dry density has great difference in frost heave laws under different moisture conditions. Fine saline soil is frost heave under high moisture content (moisture content 16% and 18%); under low moisture content (moisture content 10% and 12%), the frost heave of fine sand disappears, but the phenomenon of freezing shrinkage appears. Under the critical water content (moisture content 14%), the low temperature characteristic of the saline soil is very special, fine sand occurs cold shrink under the critical moisture content at first, and then the frost emerges as the temperature decreases. (2)Under all moisture contents and salt contents, the volume change of the saline soil is stable at -28℃--30℃, and the increased salinity will reduce the initial occurrence of salted fine sand frost temperature. Furthermore, when the salt content is less than 10%, the frost shrinkage of the soil decreases with the increase of the salt content; when the salt content is more than 10%, freezing shrinkage increases with the increase of salt content, maximum frozen shrinkage is in the middle salt content of 10%. (3)Except for the condition under critical water content, the frost heave and frost shrinkage of salted fine sand with low dry density shows cubic polynomial relation with temperature and linear relation with moisture content. Compared with other water contents, the relationship between the law of frost heave of saline fine sand and temperature under critical moisture is more complex, so the BiDoseResp function was used to fit the frost heave rate data specially, the fitting correlation coefficient is 0.997 59, which is very high. In this paper, the effects of different salt content and water content on the low temperature deformation of saline sandy soil are considered, and the specific relationship between the salt content, water content and temperature are obtained. Find the engineering properties of saline soil has obvious particularity in the cold environment, and the conclusions in this paper can provide valuable theoretical basis for the construction in saline soil area.

Key words: salted fine sand, regulation of frost heave, temperature, moisture content, salt content

中图分类号: 

  • TU448