Bearing Capacity of a Group of Stone Columns in Soft Soil Subjected to Local or Punching Shear Failures

Abstract

The use of stone columns is a viable, cost-effective, and environmentally friendly ground improvement technique. Columns are made of compacted aggregate and installed in soft soil as reinforcements to increase the bearing capacity and to reduce foundation settlement. In the literature, the methods available to estimate the bearing capacity of soil reinforced with stone columns assumed bulging and general shear as the only modes of failure. However, ground reinforced with stone columns may also fail by local or punching shear mechanisms, depending on the soil, columns, and geometry of the system. This paper presents analytical models to estimate the bearing capacity of the foundation on a soft soil reinforced with stone columns that are subjected to local or punching shear failure mechanisms. The models were based on a limit equilibrium technique and the composite soil properties. The proposed theories were validated with experimental and analytical data available in the literature. Design charts are presented for practical purposes.