摘要
膨胀土普遍发育有微孔隙与微裂隙,形成其特殊的微结构,在膨胀土脱湿过程中其内部微观结构也会发生剧烈变化,大量的研究表明,膨胀土的裂隙发育、强度衰减、胀缩变形等工程特性在很大程度上取决于其微结构特征。针对这一情况,采用扫描电镜法和压汞法相结合的方法对膨胀土原状样经抽气饱和后土体内部孔隙变化及在恒温恒湿条件下脱湿后土体内部孔隙变化进行研究,结果表明:原状膨胀土样抽气饱和后膨胀土发生膨胀,内部孔隙变小,孔隙变化主要集中在大于1μm和小于0.1μm的区域,饱和后总孔隙体积减小,但饱和前后孔隙孔径分布曲线形态基本相似;原状膨胀土样恒温恒湿环境下脱湿后,微观结构变化剧烈,总孔隙体积急剧减小,但大孔隙所占相对比例急剧增加;膨胀土脱湿干燥时孔隙收缩,土中的大孔隙变为小孔隙,导致小孔隙和超微孔隙增多,土样中的总孔隙体积减小。
Micro pores and micro fractures are common development of expansive soils,and their special microstructure is formed,the internal microstructure of the expansive soil will be changed dramatically in the process of soil moisture,a large number of studies show that： the engineering properties of expansive soil,such as crack development,strength attenuation and expansion and contraction deformation,largely depend on the microstructure of the soil. In view of this situation,SEM and MIP are used to study undisturbed expansive soil. The main conclusion is as follows： The undisturbed expansive soils are expanded,and the internal pores become smaller,the pore changes mainly concentrated in the area of more than1μm and less than 0. 1μm. The total pore volume decreases,but the shape of the pore size distribution curve is similar to that of the saturated soil; Undisturbed expansive soils are dewetted under constant temperature and humidity environment,micro structural severe changed,the total pore volume decreased dramatically,but the relative ratio of large pore has increased dramatically; When the expansive soil dehydration,the pores is shrinking,and the large pores become smaller,which leads to the increase of small pores and micro pores,and the total pore volume decreases.
出处
《武汉轻工大学学报》
2016年第1期70-74,81,共6页
Journal of Wuhan Polytechnic University
关键词
膨胀土
脱湿
微观结构
原状样
expansive-soil
dehydration
microstructure
undisturbed-example
