Behaviour of clay reinforced by sand compaction pile with smear

Abstract

In the design practice for sand compaction piles (SCPs), it is usually assumed that the state of in situ soil does not change during the installation. In fact, there is evidence to suggest that extensive remoulding of the preferred soil fabric occurs within the zone immediately surrounding the SCP. Properties of the soil within this heavily disturbed zone can affect the pore pressure dissipation, and hence the time after which the ultimate strength of the composite ground would be available. In this study, the effect of smear zone around SCPs is modelled in the laboratory using triaxial tests. SCPs of 25–80 mm diameter were installed in 100 mm diameter cylindrical samples. The sand columns were installed by pre-drilling a hole and then backfilling it with well-compacted sand. The smear zone was created by using a rough casing to drill the hole. The effect of the smear zone on SCP was investigated by observing the change in pore pressure during consolidation and the undrained shear strength of the composite sample. Although the shear-induced pore pressures and the undrained shear strength of the composite samples could reasonable be predicted, wide scatter still existed in the relationship between the stress concentration factor and the area replacement ratio.

Suitability of Fly Ash-Cement Kiln Dust Columns for Stabilizing Expansive (Black Cotton) Soils

“…These techniques include compaction using vibro-replacement, vibro-flotation, preloading with and without vertical drains, dynamic consolidation, grouting, soil stabilization, soil reinforcement, and the installation of sand or stone columns. (Juneja & Mir, 2012). The latest improvement among these methods is the study of in-situ columns.…”

Coupled discrete element–finite difference method for analysing the load-deformation behaviour of a single stone column in soft soil

“…The deformation of stone columns installed in clay has been the subject of an extensive number of experimental and numerical modelling studies (Poorooshasb and Meyerhof 1997;Ambily and Gandhi 2007;Chai et al 2010;Black et al 2011;Castro and Sagaseta 2011;Cimentada et al 2011;Fattah et al 2011;Sivakumar et al 2011;Castro and Sagaseta 2012;Hanna et al 2013, Han andYe 2002, among others). Stone columns reduce the drainage paths in soft clay, which accelerates consolidation and increases the load carrying capacity due to the subsequent reduction in settlement (Guetif et al 2007;Chai et al 2010;Indraratna et al 2013;Sivakumar et al 2011;Ali et al 2012;Juneja and Mir 2012;Tandel et al 2012). Upon external loading, stone columns distribute the applied stress and deform laterally, especially in their upper zones, rather than transfer the stresses into the deeper layers.…”

Editorial

“…The final paper by Juneja and Mir (2012) of the Indian Institute of Technology, Bombay, studies the behaviour of clay reinforced by sand compaction piles with smear in a triaxial cell. The effect of the smear zone on the sand compaction piles was examined through the pore pressure changes in the soil sample.…”