Abstract:

For the plane strain problem of engineering construction in loess area, the plane strain shear tests on intact loess under different lateral consolidation pressures and moisture contents were carried out by using the transformational true triaxial apparatus of Xi’an University of Technology. The experimental measurements of angle of inclination for shear band at shear failure were obtained. The Mohr-Coulomb and Roscoe solutions to angle of inclination for shear band of were derived from the stress-strain curve. The changes of intact loess strength, failure mode and angle of inclination for shear band were analyzed. The study results show that the stress-strain curve vary from primary softening type to secondary hardening type wih the development of new structure when the water content and lateral consolidation pressure increase. The failure modes of shear band present single line-shaped, cone-shaped and X-shaped as the increase of lateral consolidation pressure. Along wih the increase of moisture content, decrease in the cohesion, internal friction angle leads to reduce the angle of inclination for shear band of Mohr-coulomb solution, while the enhanced dilatancy rising the Roscoe solution. With the increase of lateral consolidation pressure, both the dynamic internal friction angle and the dilatancy are increase, resulting in shear band inclination angles of Mohr-Coulomb and Roscoe solution increase.

Key words: plane strain test, loess, stress-strain relationship, Mohr-Coulomb shear band, Roscoe shear band