抄録
A series of consolidated undrained triaxial tests with pore pressure measurement was carried out to study the effects of applied back pressure on the shear strength characteristics of a normally consolidated clay. Four magnitudes of back pressure were employed as being representative of a common commercial test situation, the approximate in situ neutral pressure, a pressure that ensured complete sample saturation, and a back pressure much in excess of that required for saturation.The results of the work indicate that, when a low back pressure is used in conjuction with a low consolidation pressure, the soil exhibits an apparent overconsolidation, as evidenced by the normalized stress-strain characteristics, the pore pressure parameter A^- during shear, the non-linearity of the strength envelopes, and the shapes of the stress paths. The total and effective strength envelopes for samples tested at the higher back pressures show no cohesion intercepts, while under low back pressures appreciable intercepts exist.
