Performance of geogrid-encased stone columns in soft ground: full-scale load tests

Abstract

ABSTRACT: The geogrid-encased stone column (GESC) system, which increases the confinement effect, has been developed to improve the load-carrying capacity of stone columns. This paper presents the results of an investigation on improvement in load-carrying capacity and settlement reduction of a GESC using field-scale load tests. Also, the effect of the geogrid encasement length and column strain is investigated. In addition, isolated GESC behaviour was compared to rammed-aggregate pier (RAP) and conventional stone column (CSC) behaviour. The results show that additional confinement provided by the geogrid encasement increased the stiffness of the stone column and reduced the settlement of the soft ground. Also, bulging of the GESC was observed to occur directly beneath the base of the geogrid encasement. The improvement in the performance of GESC was found to be significant, even with partial encasement.