Settlement assessment of soft soil reinforced by partially penetrated by soil cement column

Abstract

Soil cement column technique is one of a widely used technique in ground improvement over the past 50 years. The technique involve process of soft soil replacement with mixed materials in order to increase the bearing capacity and reduce the settlement. A preliminary chart of both bearing capacity and settlement of soft soil improved by floating soil cement column were developed in this study. A series of numerical modelling were performed by PLAXIS 3D with different area improvement ratio, and column height, Hc. Three (3) improvement area ratio of 20.7%, 31.0% and 41.0% and two (2) height of column were implemented which 50 mm and 100mm that is correspond to improvement depth ratio of 0.25 and 0.5. Another important parameter are cohesion ratio, and K. For analysis, two loading condition were applied on untreated and treated soils. The first load condition to identify ultimate bearing capacity or failure process. Firstly, condition of determined the ultimate bearing capacity. After that, the settlement analysis was performed by the used of working load of two third of ultimate load. The second load condition was conducted under design load to identify settlement and failure pattern. Then, a settlement charts were developed to predict the settlement of model treated with soil cement column. The 3D numerical results showed that the bearing capacity of soft soil increase with an increment of improvement area ratio, depth improvement ratio and cohesion ratio.As well as the settlement that reduced as the improvement area ratio, depth improvement ratio and cohesion ratio increased. A non- dimensional analysis was also developed to fully understanding the behavior of soft soil improved by floating soil cement column.