Undrained triaxial compression test of Nanjing silt

The undrained tests of conventional triaxial compression on Nanjing silt were conducted by the KTG to investigate the effect of confining pressure and dry density on the stress-strain curves,pore water stress-axial strain curves and effective principal stress ratio curves.It was confirmed that silt appears to be weak strain softening under high confining pressure,but exhibits strain stabilization under low confining pressure.In the first loading stage the pore water pressure of the specimen under low confining pressure remains positive,then with the loading incease pore water pressure decreases to negative until that tends to be stabe.The more is principal stress deviator peak,the more possible is to emerge negative pore water pressure and to show more shear dilatation with high dry density.When the dry density is relatively high,this dense specimen shows shear dilatation characteristics,and the effective principal stress ratio tends to be strain softening phenomenon.When the confining pressure is relatively low and dry density is comparatively high,the specimen is apt to show the softening characteristics,and the shear band failure emerges in specimen,the strength drops greatly.