滨海地区粉质黏土渗透特性试验

Experiment analysis on permeability of silty clay in coastal area

以上海第(6)层粉质黏土为例,研究了固结压力、各向异性及结构性对滨海地区粉质黏土渗透特性的影响,并通过电镜扫描(SEM)进行粉质黏土微观渗透机理的分析。研究表明,粉质黏土渗透系数随着固结压力增大而减小,粉质黏土水平方向的渗透性大于垂直方向;重塑土因受扰动渗透性反而变小。微观分析显示,固结压力增大使得土颗粒间的孔隙变小;垂直方向存在较多粒状聚体,而水平方向则以片状或板状聚体为主;重塑土受扰动后小颗粒填充了大孔隙。粉质黏土颗粒间的孔隙类型、接触方式等微观结构变化,是其宏观渗透性差异的根本原因。

The impact of consolidation pressure anisotropy and structures are studied on the permeability ofsilty clay respectively by using the sixth layer soil in Shanghai.Then the microstructure and permeation mechanismare discussed by using scanning electron microscopy. It is revealed that permeability coefficient decreases with theincrease of consolidation pressure ; and the horizontal permeability is greater than the vertical permeability; th epermeability of remolded soil will decrease when compared with the undisturbed soil.Moreover, the microscopicanalysis indicates that consolidation pressure makes the soil more compact there are many granular polymers in thevertical direction while flaky or planar polymers dominate the horizontal direction.The soil is disturbed and the smallparticles are filled with large pores.The changes of pore types and contact modes between the granular clay particlesare the essential reasons for the macro permeability difference of silty clay.