To increase the bearing capacity of soil especially when underneath soil is of clayey matter sand piling is adopted. This is considered as a soil stabilization method rather than piling method of load transfer.
Principle
Sand pile acts upon soil in two ways
1. Lateral compaction
2. Consolidation effect
1.Lateral compaction:- Sand piles are driven into the soil. This increase the density and bearing capacity of soil.
2. Consolidation effect:- Consolidation is a process by which soils reduces its volume. It occurs when over burden pressure or surcharge is applied to a soil that causes the soil particles to pack together more closely, therefore reducing its volume. When this occurs in a soil that is saturated with water, water will be squeezed out of the soil .This effect is predominant in the clayey soil. Clayey soil has very low permeability. A surcharge is added to clayey soil it will take very long time to consolidate if sand pile is not provided. Sand pile act like a sand drain so that water trapped inside the clay can easily escape and the volume reduction will be very fast.
