Acta Scientiarum Polonorum

The influence of shear velocity on shear resistance of a sandy clay at different moisture content and stress
level during direct shear tests is investigated. The stress ratio and dilatancy relationship gives a new possibility
of interpreting the results of direct shear tests results. The mobilized shear resistance is a function of
pore pressure in a shear band and possibility of this pressure dissipation into the upper and lower part of the
sample. The pore pressure in a shear band is an effect of volume changes and filtration of water from the shear
band. Generally, at failure, the pore pressure in the shear band is a function of initial moisture, stress level
and shear velocity. At failure, the pore pressure is negative for low moisture and low stress level, and positive
for high moisture of soil and high stress level. Moisture level, stress level and shear velocity have significant
influence on shear resistance of soil.