长春季冻区路基土微观孔隙特征的定量评价  

QUANTITATIVE EVALUATION OF MICROSTRUCTURE FEATURES OF PORES IN SUBGRADE SOIL IN SEASONAL FROST REGIONS OF NORTHEAST CHINA

作　　者：赵安平[1] 王清[1] 李杨[1] 车茜[1] 

机构地区：[1]吉林大学建设工程学院,长春130026

出　　处：《工程地质学报》2008年第2期233-238,共6页Journal of Engineering Geology

基　　金：国家自然基金项目(40672180)

摘　　要：路基冻害一直是困扰东北季冻区道路建设的一个重要问题。长春冬季天气寒冷,在温度梯度作用下路基土中水分产生迁移和聚集,引起路基冻胀。春季路基解冻,集聚的冰晶体融化,路基土处于饱和或过饱和状态,承载力极低,在交通车辆作用下发生路面鼓包、弹簧、断裂和翻浆冒泡等现象,给交通运输和经济建设带来极大的危害。孔隙是水分迁移的主要通道,是影响路基冻胀主要因素之一,其特征决定土体的冻胀敏感性。本文利用WD-5配置联机图象处理系统的电子显微镜,通过图像定量分析系统,对长春季冻区路基土的微观孔隙作了定量评价。经过分析得出:3个土样孔隙直径均是小于5μm的占主导地位,都具备冻胀条件;试样水平和垂直两个方向的孔隙分布较均匀,孔隙为辐射状或网状结构,多为扁圆和等轴形状;孔隙形态分维数分析认为,分维数高,大孔隙含量多,孔隙分布比较简单,在研究范围内,有利于水分迁移,冻胀性较强。Subgrade freeze - thawing injury is an important problem that has puzzled man al frost regions of northeast China such as the cit of Chang - chun. In winter, weather in y engineers in the season- Chang - chun is very frigidity. Water in subgrade is moving and assembling in some positions under gradient of ground temperature So, S e and ice lenses which assembled in some positions begin thawing. The subgrade soil is in saturation or over saturation states. The bearing vehicles, bulges, elastic springs, fractures and soil boiling can communication, transportation, and economic construction. It factor that affects frost heave. Pores as one of important symbo capacity is very low. Under the action of traffic appear on pavement, which give very bad injuries to is urgent and necessary to research every influencing ls of soil structure are main entryways of water movement in soft. They decide sensibility of frost heave of the soil. In the paper, the WD - 5 SEM is used to collect microstructure photos of soils from three different locations nearby Chang - chun. The photos are further used to make quantitative analysis to microstructure of pores in soil. An image quantitative analysis system is used. The quantita- tive analysis results in the finding that microscopic pore diameters of three samples are mainly about 5 μm. This pore size makes softs have property of frost heave. There arent noticeable difference of microcosmic pores between vertical and horizontal sections from a same sample. There are radial or reticular structure of pores, and shapes of oblate or equiaxial. The analysis further leads to the finding that when pore shape fractal dimensions are higher,there are many big pores, and the pore distribution is simple. The research site is suitable for water movement in the subgrade, therefoe, the frost heave is strong.

关 键 词：冻胀 翻浆 微观结构 孔隙特征 图像定量分析 分维数 

分 类 号：P642.14[天文地球—工程地质学]