Bearing characteristics and mechanism of confined stabilized soils

The stabilized-soil cylinders are made by mixing the soil samples with the relative water content from 0.26 to 1.19 with the binders containing different contents of expansive components, and then they are put into PVC constraint tubes with length of 20 cm, external diameter of 11 cm and different confinement stiffnesses. The hoop expansion strains of the constraint pipes are measured during curing period. The compressive experiments on the cylinders are carried out, which are pressed respectively with and without the constraint pipes. The load-hoop strain curves of the cylinders, load-displacement curves and the failure modes of the cylinders are recorded. The conclusions are as follows: (1) The bearing capacities of the confined cylinders are 5 times those of the unconfined ones made of the ordinary binder with the same binder content. The equivalent strength of the confined stabilized soils can reach more than 30 MPa, which is calculated according to the data of its bearing capacity and cross-sectional area. (2) Combining the constraint with the binder containing expansive components results in unique effects: the binder expansion is confined to compact the core-stabilized soils so as to increase the strength obviously. The prestress upon the core-stabilized soils can be built, which with the hoop constraint the core-stabilized soils are made to be in triaxial compressive stress state under bearing load. (3) The load-displacement curve of the confined cylinders shows three stages: linear stage 1, approximately linear stage 2 with smaller slope and stage 3 with almost zero slope. (4) At the stage 1 the core-stabilized soils resist vertical load as a cemented entirety, at the stage 2 they are crushed gradually into pieces and resist further increasing load with help of hoop constraint force, and reach the ultimate bearing capacity because of the constraint losing its effectiveness.