低干密度盐渍细砂土低温特性试验研究  

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

作　　者：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 PAN Gao-feng WU Ya-ping LIU Zhen ZHANG Xiao-bo LI Jun-yu CHEN E ZHOU Yong(School of Civil Engineering,Lanzhou Jiaotong University,Lanzhou 730070, Gansu, China Jiangsu Testing Center for Quality of Construction Engineering Co. ,Ltd. ,Nanjing 210028 ,Jiangsu, China Inner Mongolia Transit Design and Research Institute Co., Ltd.,Hohhot 010000, China Traffic Planning Surveying ＆ Designing Institute of Shanxi Province, Taiyuan 030012, Shanxi, China Qinghai Local Railway Construction Investment Co.,Ltd. ,Xining 810000, Qinghai, China)

机构地区：[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

出　　处：《干旱区地理》2017年第1期131-137,共7页Arid Land Geography

基　　金：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)

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。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

关 键 词：盐渍细砂土 冻胀规律 温度 含水率 含盐量 

分 类 号：TU448[建筑科学—岩土工程]