Investigation On Mechanical Behaviors Of Underconsolidated Clay Under Multidimensional Stress Path

In traffic engineering,embankment filling and traffic load cause multi-dimensional change of stress state of soil element in different spacetime positions in subsoil,which often leads to excessive settlement of underconsolidated clay subgrade.In view of this engineering problem,the effect of multidimensional coupled directional shearing and intermittent cyclic dynamic loading on the static and dynamic characteristics of soft clay with different consolidation degrees was studied.By controlling vertical deformation,consolidation time and dissipation degree of excess pore water pressure,underconsolidated clay samples were prepared by using the self-developed underconsolidated clay sampling apparatus and the hollow cylindrical specimen cutting apparatus.The consolidation degree has a significant influence on the development of directional shearing stress path of soft clay.The length of total stress path gradually increases with the increment of consolidation degree.In contrast,total stress path of normally consolidated clay is the longest,and test specimen reaches failure state at the latest.During directional shearing process,the evolution of excess pore water pressure is the result of stress condition and consolidation degree of soft clay.For the development of axial strain and circumferential strain,the direction angle of major principal stress and consolidation degree of soft clay play an important role.However,it has little effect on the development of radial strain.The isotropic variation of size,position and covered area of shear strength envelope of soft clay with different consolidation degree indicates that the consolidation degree is the significant factor determining its deformation resistance and shearing strength.The intermittency and continuity of multidimensional cyclic dynamic loads jointly determine the critical dynamic stress level corresponding to both the evolution of water pressure and axial strain cumulation in the underconsolidated clay.