Effect of Stone Columns on the Behaviour of Single Pile in Soft Clay Soil

Abstract

Soft clay is consolidated upon any slight change in the effective stress. Consolidation and settlement of soft clay surrounding a pile usually drag the pile down ward. The down drag movement adds additional loads to the already loaded pile. This force is expressed as a negative skin friction. Negative skin friction starts from the pile head to a neutral depth depending on the interface properties. This depth is referred to as the neutral plan. This paper presents a study on the effect of stone columns on the behaviour of piles during consolidation of soft clay soil. For this goal the experimental tests were done to study effect of stone columns on the behaviour of single pile embedded in soft clay. The study concluded that the neutral plane is located closer to the end of the pile as the end bearing increases. Stone columns are considered one of methods used to reduce the settlement of soft clay soil, and helps to speed up the rate of consolidation by shorting the length of drainage path within the soft clay layers, and then decrease the relative displacement between the pile and the surrounding soft soils. The use of stone columns reduced the amount of negative friction developed along the pile depth.