疏浚土固化前后的压缩模量及微观结构变化的定量研究

在不同养护龄期和固化剂掺量的条件下,用WK-G1固化剂对横沙岛区疏浚土进行了固结试验,得到固化疏浚泥的压缩模量Es与固化剂掺量、养护龄期之间的关系;并利用电镜扫描(SEM)对其中某一特定固化剂掺量和不同龄期下的固化疏浚土的微观结构进行观测。运用IPP图像处理软件和Matlab编程对固化土SEM图像进行处理,得到固结过程中不同龄期下的粒度分维D_(ps)和孔径分维D_(bs)、颗粒分布分维D_(pd)和孔隙分布分维D_(bd)、颗粒表面起伏分维D_(pr)以及颗粒和孔隙的个数、平均面积、平均直径等微观结构参数。并对微观结构参数和分维数与压缩模量的关系作了定量分析。结果表明:在WK-G1固化剂固化疏浚土的过程中,压缩模量Es随着龄期和固化剂掺量的增加而显著增大;微观结构方面表现出土颗粒数增多,颗粒分布集中,平均粒径和颗粒平均面积增大,颗粒表面起伏变大,颗粒逐渐均一化;孔隙数增多、平均孔径变大、孔隙平均面积减少、孔隙更加分散,均一化变差;各分维值与龄期和压缩模量具有高度的线性关系,相关系数R~2可达0.97。

The study of compression modulus and changes in microstructure of dredged mud before and after solidification

The consolidation test for dredged soil was designed to study the compression modulus Es of cured dredged mud from Hengsha island at different curing period and curing agent content by using WK-G1 curing agent .The microstructure of cured dredged mud with a specific curing agent content and different curing period was observed by using Scanning Electron Microscope. The quantitative calculation of microstructure parameter and fractal dimension was done by the SEM images of cured dredged mud at each curing period,and got the particle and pore size fractal dimension, particle and pore distribution fractal dimension, particle surface fractal dimension and the number of particle and pore, the mean area, mean diameter. And quantitatively analyzed the influence of microstructure parameter and fractal dimension for the macromechanics parameter by combinning with the macromechanics parameter that got by indoor experiment. The research results show that the compression modulus increased with the curing period and curing agent content significantly. And the change of each fractal dimension and microstructure is remarkable. The fractal dimension value and compression modulus has a high degree of linear relationship and coefficient of correlation R₂is near to 0.97.