Performance of High Confined Stone Columns in Pond Ash Fills an experimental and numerical study

Abstract

Vertical encased stone columns are a ground modification technique that improves the bearing capacity and reduces the total displacement of soft and loose cohesionless soils, which gain strength through the skin friction of surrounding soils and end-bearing of the column. However, these stone columns (SCs) are limited in their ability to carry vertical and lateral loads due to the low radial pressure offered by the adjoining soft or cohesionless soil. The SCs experience bulging due to the squeezing of column aggregates. newlineThe present study investigates the performance of highly confined stone columns, which are encased with vertical and horizontal reinforcement of the aggregates, pervious concrete columns with under-reamed single bulbs constructed in loose cohesionless soil. The performance of these highly confined columns was studied under varying conditions such as tensile strength of the encased material (geosynthetics), pervious concrete without and with under-reamed single bulbs, slope stability, group action, and piled-raft on soil improved with the combined effect of ordinary and encased columns. newlineA physical examination was conducted in the laboratory using a model tank, model footing, a load cell, and dial gauges for load and deformation measurements. The materials used were pond ash as loose cohesionless soils, recycled concrete aggregates as column fill material, geotextile for vertical encasement, geogrid discs for aggregate reinforcement, and pervious concrete with no fines. The preliminary geotechnical parameters of all the materials were studied to achieve the objectives. newline newline