Abstract:

To investigate macroscopic mechanical properties and microstructure evolution mechanisms of Nanjing Xiashu soil under triaxial compression, triaxial apparatus and scanning electron microscope（SEM）were used respectively to perform a series of experiments. Results show that the ratio of structural strength of Xiashu soil to confining pressure is almost a constant, and the structural strength depends on internal particles arrangements of soil, bonding capacity between particles and outer stress states. As shear strain of soil increases under triaxial compression, greater particle aggregates are sheared breakage, and smaller ones enlarge by gathering together, resulting in increase of particle area ratio but reducing its collectivization degree and scattering its planar distributions. Consequently, the particles arrangements gradually tends to disorder, and finally shear failure zone forms in the most disordered part.

Key words: triaxial compression, Xiashu soils, deformation, structural strength, microstructure, soils