动荷载作用下结构性软土微结构变化的分形研究

为探讨天津滨海新区典型结构性软土的动力特性，采用动三轴试验和压汞试验，对交通荷载作用下结构性软土微观结构变化进行了研究。取原状土和动荷载作用后的土样进行压汞测试，用分形理论对压汞测试数据进行分析，探讨孔隙分布特征，提出孔径划分的方法，给出了卓越频率与土体孔隙变化的规律。研究结果表明：在动荷载作用后，天津滨海新区典型软土的孔隙分布发生改变，可分为3种类型；利用Menger海绵模型研究交通荷载作用下结构性软土的孔隙分布特性是可行的；用孔隙分维数可实现对卓越频率的预测以及路基土体变形行为的机制分析。

Fractal study of microstructure variation of structured clays under dynamic loading

In order to understand the dynamic characteristics of the structured soft soil in Tianjin Binhai Area, dynamic triaxial test and mercury intrusion test are applied to measure microscopic features of structured clay. The microstructures of unloaded and loaded soft soils are studied by means of the mercury intrusion tests. The fractal theory is used and the fractal characteristics of pore distribution are studied through the data analysis. The method of pore classification is proposed; and the relationship between porosity feature and excellent frequency are formulated. The results indicate that the pore of structured clays under traffic loading is able to be divided into three types according to relation curve of pore diameter and volume of the structured clays. Menger sponge model can be applied to fractal research of the pore characteristics of structured clays under traffic loading. The porosity fractal dimension can be employed for predicting the excellent frequency and analyzing soil deformation mechanism under the embankment.