1-g physical modelling of shallow foundation treated with polypropylene-reinforced soil-cement columns in liquefiable soil

Abstract

The fibre-reinforced soil-cement columns are used as remediation measure against earthquake induced soil-liquefaction associated large settlements in liquefiable loose surface layer of sand. This loose surface layer of sand was overlying on the non-liquefiable dense bottom layer of sand. 1-g physical modelling of shallow foundation was carried out using shaking table. There were four 1-g physical models constructed for testing and the two types of improvements were used such as adjacent and beneath the structure. First model was 1-g physical model constructed without improvement, and three models were constructed with the provision of polypropylene-reinforced soil-cement columns. In the first treated model the columns were installed in the wooden fixity plate and adjacent to the structure, the second treated model was improved with improvement installed upon the soil-cemented fixity plate and provided adjacent to the structure, and in the third treated model with improvement installed upon the wooden fixity plate and provided beneath the structure. The results obtained in case of untreated 1-g physical model concludes that the penetration of structure inside the soil and settlement of structure, both are up to unacceptable limits. The results of first treated 1-g physical model concludes that the penetration and settlement of structure both are unacceptable. The results of penetration and settlement of structure in the case of second treated 1-g physical model are achieved up-to acceptable limits. The most successful type of improvement against the liquefaction-induced penetration and settlement of structure was achieved in case of third treated 1-g physical model in which the values of settlement and penetration are negligible. It is concluded that the improvement installed upon wooden fixity plate and provided beneath the structure is relatively the most efficient remediation measure against the earthquake induced soil-liquefaction induced settlement of structure.