SHEAR STRENGTH OF SOFT CLAY REINFORCED WITH ENCASED LIME BOTTOM ASH COLUMN (ELBAC)

Abstract

Soft clay soils are problematic soilthat causes bearing capacity failure and excessive settlement,
leading to severe damage to buildings and foundation. In this study, bottom ash is used to replace the natural
aggregate while quicklime is used to increase the bonding between bottom ash particles. This research is aimed
to investigate the role of single encased lime bottom ash column (ELBAC) in improving the shear strength by
using laboratory scale model. Kaolin is being used as soil sample while lime bottom ash as the reinforced
column and the column is encased with non-woven geotextile. Laboratory tests are conducted to determine the
physical properties of bottom ash, kaolin clay, and quicklime sample. Unconfined Compression Test (UCT)
also used to test the shear strength of the reinforced kaolin samples. There are 21 kaolin samples being tested
in this study and the dimension of the specimen used is 50mm in diameter and 100mm in height. However,
there are two different types of the diameter of single lime bottom ash column being used which are 10mm and
16mm. The heights of the column are 60mm, 80mm and 100mm. The improvement of shear strength ofsingle
encapsulated lime bottom ash column with area replacement ratio of 4.00% (10mm column diameter) and
10.24% (16mm column diameter) are 43.58%, 50.00%, 49.17% and 38.08%, 42.67%, 32.75% at sample
penetration ratio, Hc/Hs of 0.6, 0.8 and 1.0 respectively. It can be concluded that the shear strength of soft clay
could be improved by the installation of the single encapsulated lime bottom ash column.