Critical state parameters derived from constant cell volume triaxial tests

Abstract

SummaryCritical state parameters were determined in constant cell volume triaxial tests on three remoulded agricultural topsoils, a sandy loam, a clay loam and a clay. Tests were made at a range of water contents. The normal consolidation lines tended to be linear on a semi‐logarithmic plot up to a degree of saturation of c. 0.85, above which the soil was incompressible but highly deformable. The slopes of the projected critical state lines were slightly greater than the slopes of the normal consolidation lines for all three soils. For each soil, both lines pivoted about a point as water content increased and, for the two lighter‐textured soils, the increases in compactibility tended to be greatest near the plastic limit. For all three soils, strength remained fairly constant with increasing water content until the soil was at around 70‐85% of the cone penetrometer plastic limit. Strength then decreased with increasing water content, with the smallest decrease in the sandy loam.