Shape Columns Settlement For Free

The stone column is one of the effective ground improvements that is increasingly used to support different infrastructures and buildings built on soft clay soil. Many studies have proven that a single column incorporates three different failure modes: bulging, punching, and shear.

When the columns are installed, the area replacement ratio is defined as the ratio of the cross-sectional area of a column to the tributary area of the column, as shown in Figure 1. Under rigid loading, the stress distribution on the columns and the soil can be simplified as shown in Figure 2.

The key parameters relevant to the design of floating stone columns include the area replacement ratio, the friction angle of the column material, the loading intensity, and the post-installation earth pressure.

As a first approximation, a general value of the critical column length of 2 and 2.5 times the footing diameter may be considered for ordinary and encased stone columns, respectively.

The area replacement ratio ( ) is the ratio between the area of the columns and the loaded area, i.e. footing area in this case. For the reference case, the footing diameter, , is 2.5 m and the column diameter ( =1.37 m) was chosen to give an area replacement ratio of = 30%.

Stone column ground improvement involves adding vertical columns of stone into the ground to a depth of at least 4m below the ground surface. A layer of compacted gravel can then be put over the top of the columns, ready for the construction of new house foundations.

An optimum area replacement ratio of 30?40% exists for the control of settlement. The settlement performance of a small column group is highly influenced by inter-column and footing interaction effects.