摘要
黄土结构疏松、水敏性强,在水力作用下,易导致强度骤降,水稳性减弱甚至丧失。黄土中水分以自由水、结合水等多种形式存在于土的孔隙中,孔隙的分布特征是决定土中水分存在和变化规律的主要因素。该文基于压力膜仪试验,结合孔径分布的计算理论,做出了土水特征曲线和孔径的分布曲线,并结合分形理论,以分形维数为孔隙分布规律的评价指标,建立不同工况下黄土的含水状态变化特性与细观孔隙分布特征间的关系。结果表明,土中孔隙越小,分形维数越大,土的含水状态变化越不明显;土的残余含水率与分形维数呈线性相关,残余含水率增高的同时,分形维数和土体的持水能力也增大;土的进气值与分形维数呈正相关,但不呈线性关系;土中的大孔隙越多,土的进气值就越大,分形维数越大。
Loess soils in situ usually possesses meta-stable structure and strong water sensitivity,which enables them easily to lose strength and water stability under the wetting condition.There are various types of water in the soil voids,including free water and bound water.The distribution characteristic of voids in the soil dominants the existence and variation of the water content.Based on the pressure membrane instrument test,and combined with the pore size distribution analysis theory,the soil-water characteristic curve and the pore size distribution curve are obtained.Furthermore,on the basis of fractal theory,the fractal dimension is used to evaluate the pore size distribution law,and the relationship between the water content and the micro pore size distribution characteristic of loess under different conditions are studied.The results show that with the decrease of the pore size in the soil mass,the fractal dimension is increased,and the variation degree of water content is decreased.Meanwhile,the residual water content is linearly related to the fractal dimension,i.e.,the fractal dimension and water retention capacity of loess is increased with the increase of the residual water content.Moreover,the air entry value is positively,but nonlinearly related to the fractal dimension.With the increase of large pores in the soil mass,the air entry value is increased,which leads to a larger fractal dimension.
作者
廖红建
刘少华
何玉琪
孙俊煜
LIAO Hongjian;LIU Shaohua;HE Yuqi;SUN Junyu(School of Human Settlement and Civil Engineering, Xi′an Jiaotong University, Xi′an 710049, China)
出处
《西北大学学报（自然科学版）》
CAS
CSCD
北大核心
2022年第3期416-422,共7页
Journal of Northwest University（Natural Science Edition）
基金
国家自然科学基金(51879212,41630639)
陕西省国际科技合作计划重点项目(2019KWZ09)。
关键词
非饱和黄土
孔径分布
分形理论
持水特性
unsaturated loess
pore size distribution
fractal theory
water holding capacity
