摘要
为从微观角度研究冻融循环条件对天然盐渍土结构的影响,以罗布泊地区一定深度的天然盐渍土为试样,进行了室内3、5、7次冻融循环试验,在每次试验后测定土样的密度、含水率,并利用SEM提取微观结构图片,进而对试验后的土样在1000倍放大扫描电子显微镜下的微观结构变化进行分析。研究结果表明:随着冻融循环次数的增加,水分自下而上向冷端迁移,冷端含水率较高;土样的密度不断减小,且在深度方向呈现出不规则的正"3"字形的变化规律。冻融前后土体微观结构特征明显不同,经过冻融循环后,土体颗粒间孔隙增大,密实度降低,内部骨架结构发生位移,易引发土体盐胀变形、翻浆、溶陷等不良现象,会严重影响道路工程的稳定性。
In order to study the influence on structure of natural saline soil under the condition of freezing and thawing cycle from microscopic view,using the natural saline soil sample obtained from a certain depth in Lop Nor region for indoor freeze-thaw cycling test of 3,5,7 times respectively,the soil density and water content are determined after every experiment,and then the microstructure pictures are extracted with the SEM and the change of soil microstructure is analysed under 1000 times magnification scanning electron microscope. The results show that with the increase of cycling times,the moisture migration from bottom to top of the cold side,the moisture content of cold side is more higher than other place; the soil density decrease gradually and the changing trend present as the irregular shape of ＂3＂in depth direction.The characteristics of microstructure of the soil has changed significantly before and after freezing and thawing. The gap between soil particles has enlarged,the density reduced,and the inside frame structure displaced after freezing and thawing. The salt deformation,pumping and dissolve trap may easily occur,which would influence the stability of roadbed severely.
出处
《工程勘察》
2016年第5期12-16,共5页
Geotechnical Investigation & Surveying
基金
国家自然科学基金(41262012)
新疆水文学及水资源重点学科基金(xjswszyzdxk20101202)
关键词
天然盐渍土
冻融循环
含水量
密度
电镜扫描
natural saline soil
freeze-thaw cycles
water content
density
scanning electron microscopy（SEM）
