Bearing capacity of soft soil reinforced by bottom ash columns using PLAXIS 3D

Abstract

Soft soil is usually a heterogeneous material with very different properties. The main problem of soft soil is expressed in low bearing capacity and deformations under loading (settlement). In certain regions, such issues are daunting for geotechnical engineers. In order to solve this problem, granular columns introduced as a ground improvement technique to increase the load-bearing capacity and decrease settlement by replacing the soft soil with columns group of granular materials such as bottom ash. Bottom ash is a by-product material that might be utilized as a green granular column when altering the natural source materials such as sand or aggregate. This paper studies the ultimate bearing capacity of a foundation on soft soil reinforced by five groups of end-bearing bottom ash columns using a finite-element PLAXIS 3D modelling with three different constitutive soil models. The area replacement ratio of the five groups were 13.1%, 19.6%, 26.2%, 32.7% and 39.3%. In comparison with untreated soil, the ultimate bearing capacity in soft soil increased up to three times with the increment of area replacement ratio. The obtained numerical findings were compared to existing physical modelling results carried out by previous researchers and these results have been validated through this comparison. Based on the results, the Hardening Soil model can well describe the soil behaviour with an accurate estimation for load-bearing capacity when compared to experimental outcomes.