Like most ground improvement techniques, stone columns are used to reduce settlement and increase load-bearing capacity. They also accelerate soil consolidation as a result of the drainage capacity of the granular material within the columns, which act as pore or water pressure evacuation points.

How are stone columns constructed? Stone columns are constructed by experienced contractors using specialist equipment. The construction uses an excavator with a vibrating probe to feed stone into the ground, forming a vertical column of stone.

Stone column method for ground improvement is a vibro-replacement technique, where the weak soil is displaced using a cylindrical vibrating probe (i.e. vibroflot), thus creating a column that is then filled and compacted with good-quality stone aggregates.

The term column applies especially to a large round support (the shaft of the column) with a capital and a base or pedestal, which is made of stone, or appearing to be so. A small wooden or metal support is typically called a post. Supports with a rectangular or other non-round section are usually called piers.

The stone feeding is done by stages to allow a better compaction of the entire stone column. Each time the hole is filled with stones, the Vibrolance goes down again to compact them. This process is repeated several times until the stones reach the surface.

Stone columns can be used to accelerate the consolidation of soft clay deposits through two mechanisms. First, the stone columns act as vertical drains that provide additional drainage path for excess pore water pressure to dissipate.

The effectiveness and performance of the stone column technique is influenced by several factors, including the column length to diameter ratio (L/d), the area replacement ratio (As), the column spacing (s), the stiffness of the column (Ec) and of the surrounding soil (Es), the stress ratio of the column and soil (σvc/ ...