低圧での締め固め土の剪断特性と水浸時の剪断破壊について

The routine works of shearing tests are carried on normal stress range 50 to 100kPa. This normal stress range is correspondent to overburden of 3.0 to 6.0 m. Most slipes of embankment filles occure at or after rainfalles and the thickness of most slipes are smaller than 1.0 to 2.0 m.
Using the strength parameters c and φ obtained with routine works for stability analysis, these parameters are extrapolated from results of routine works but the appropriateness of this method is scarcely examined.
In this paper, using the spesimen of compacted clay which D-value is in the range of 95% to 85%, the direct shear tests with constant pressure of the range from 10 to 350 kPa are performed under the conditions of intact and inundation.
Assuming as low pressure range to be 10-100 kPa and ordinary pressure range 50-350 kPa, there is a considerable difference between the strength parameters c and φ of low pressure range and ordinary one at the intact condition but the difference becomes less at the inundation condition. The applicability of non-linear equation for wide range of pressure is better than MohrCoulomb equation.