不同固结压力下饱和软粘土孔隙分布试验研究

Experiment Study on Relationship Between Pore Distribution and Different Stress Levels due to Consolidation of Soft Clays

土体的微结构对土的工程力学特性具有决定性影响,运用压汞试验方法对上海淤泥质粘土单轴固结过程中的不同固结压力水平下的土样进行试验,采用孔隙种类、孔隙大小两种不同的标准对上海淤泥质粘土的孔隙分布特点及孔隙的大小进行研究。研究结果表明:上海淤泥质粘土孔隙以小孔隙为主,即多以团粒内在的孔隙和颗粒间的孔隙为主,孔隙半径多分布在0.2μm-1.2μm之间。随着固结压力增大,当固结压力分别为132 kPa,264 kPa时,土体中孔隙分布仍以小孔隙为主,但小孔隙和微孔隙分布的比例有一定的变化;当固结压力增大到800 kPa时,土中孔隙以微孔隙和超微孔隙为主,试样中团粒间的孔隙几乎消失,颗粒间的孔隙占有完全的主导地位。

The soil microstructure has a significant influence on soil mechanical behavior.In this paper,the mercury intrusion tests were employed on Shanghai mucky clay to investigate the relationship between pore distribution of mercury test and stress level due to consolidation.The results show that the pore size distribution is dominant for small pore size,which is dominant for interaggregation pore and interparticle pore,with the main size distribution varying from 0.2μm to 1.2μm.with the increased vertical stress,when the vertical stress is 132 kPa,264 kPa respectively,the pore size distribution is still dominant for small pore size,but some changes happen to proportion between small pore and micro-pore;when the vertical stress reaches 800 kPa,the pore size distribution is dominant for micro-pore and smaller micro-pore,the interaggregation pore almost disappeared,the interparticle pore is completely dominant instead of interaggregation.