Stability of an Unsupported Vertical Trench in Sloping Ground

The lower bound limit analysis technique in combination with the finite elements is implemented to generate the stability numbers for an unsupported vertical long trench in a sloping ground, associated with the critical state of shear failure in a cohesive-frictional soil medium. The computational results are derived for various combinations of normalized excavation depth, friction angle of soil and slope angle. From the results of the analysis, it can be noted that with the increase in the slope angle the stability of the unsupported trench reduces drastically. With an enhancement in the magnitude of slope angle, the plastic zone in the vicinity of the trench becomes increasingly asymmetric. The results provided in this paper are expected to be beneficial from the point of view of designing vertical trench in sloping ground.