Abstract: Stepped wetting tests with stress free and compression experiments under controlled matric suction are performed on remolded Q3 loess by using refitted consolidation apparatus for unsaturated soils. The soil-water characteristic curves and compression stress-strain curves are obtained. Meanwhile, the relationship between saturation and matric suction and that between water content and suction are studied. The law of compressive yield stress varying with matric suction and that of collapsibility coefficient varying with matric suction are also studied. The results show that when the suction of unsaturated remolded loess is large, the strength of it is large and the compression deformation is small. And the structural yield pressure of unsaturated remolded loess is larger. When the suction is constant, with the increasing of pressure, the collapsibility coefficient shows a tendency of first increased and then decreased. Under the same net compression stress, the greater the matric suction of unsaturated soil is, the larger the collapsibility coefficient change sand vice versa. Once the (p = 200 kPa) is in excess of 0.1, the matrix suction will approximately exponentially increase with it.

Key words: unsaturated remolded loess, soil-water characteristic curve, suction, compression test, collapsibility coefficient