Performance of granular columns in dispersive soils

Abstract

The soils found abundantly along the Konkan belt in peninsular India are lateritic soils and lithomargic clays. The locally available lithomargic clayey soils are problematic in the sense that their strength reduces drastically under saturation conditions, which is typical behaviour of the dispersive type of soil. Most foundations are placed on this soil layer. This paper presents results from a series of laboratory plate load tests carried out in unit cell tanks to investigate the behaviour of granular columns in these weak (lithomargic clay) grounds. Tests are carried out with two types of loading: with the entire area in the unit cell tank loaded, to estimate the stiffness of the improved ground; and with only the granular column area loaded, to estimate its limiting axial capacity. Investigations were carried out by varying the area ratio (or spacing), diameter of granular columns, end condition and column configuration. The load-settlement behaviour, stiffness and bulging behaviour of granular columns are analysed. It is found that the ground treated with granular columns exhibits a high load-carrying capacity and stiffness, and a significant reduction in settlement, compared with the untreated ground.

Editorial

“…This then allowed treatment resulting in increases in clay shear strength by up to 20 times. The final paper continues the theme of ground improvement and soft/ problematic soils through the use of granular columns in the difficult dispersive conditions found in the Konkan Belt in India (Nayak et al, 2014). The paper shows that although lateral bulging up to 25% occurred, there was still significant potential for improvements to surface foundations.…”

Evaluation of Stability of Embankment Constructed on Soft Consolidating Soil with Lime–CFG Composite Column System

“…Construction of embankments on sites once considered as unsuitable is becoming greatly inevitable nowadays due to limited availability of appropriate sites and fast-increasing urbanisation. The rapid growth of infrastructure facilities has necessitated the expansion of construction activities in areas with poor subsoil conditions [1]. Due to the presence of various problematic soils, embankments constructed on these type of soils show large settlement and excessive pore water pressure.…”