Ground Improvement with Stone Columns–A Review

Abstract

Soil improvement is rapidly gaining importance due to the paucity of good quality land for development, structures, and transportation infrastructures. A range of soil improvement methods is available amongst which stone column is one of the most efficient and effective techniques. It is generally used to improve soft and weak soil, having less bearing capacity, high compressibility, and high settlement. The improvement is due to its higher stiffness compared to the surrounding ground, and it is measured in terms of stiffness improvement factor. The stone column is designed as per IS 15284-2003 and is usually analyzed by using the unit cell concept. They are generally constructed using crushed stone aggregates and are ideally installed in an equilateral triangle pattern. The failure of the stone column is dependent on its critical length. This review paper is aimed to study some exemplary practices done while designing, constructing, or installing the columns. It also intends to analyze the effects of these practices, which include the pros and cons of each method. Some modifications include geotextile or geosynthetic-encased stone columns, rubber-drained columns, lime-fly ash columns, lime-mortar soil columns, and a column for liquefaction mitigation. Hence, it aims to access the suitability of these practices in the coming future to have increased effectiveness and overall efficiency. Further, some suggestions are made regarding the construction practices which may be pertinent in the near future.