Pile foundation is used when the soil immediately below the foundation cannot safely support the loads and load has to the transferred deep into the underlying soil. It is required when soil bearing capacity of the soil is not sufficient for the structure. The main function of the pile is to transmit loads to the lower level of the ground by the combination of friction pile and end bearing pile at the pile point or base.
The Pile foundation consists of two major components: Pile cap and single pile or group of piles. Pile cap supports the single column or group of columns. Piles transfer the loads from the structures to the hard strata in soils having a low bearing capacity or in the structure in the water like dams and bridges.
There are Different Types of Pile :
There are two basic kinds of pile, those that displaces the ground and those that replace the ground in which they are placed.
The Most Commonly Practised Types of Concrete Pile are:
01. Displacement Type Pile in Concrete:-
- Driven and cast in place
- Precast RCC pile or pre-stressed driven pile.
02. Replacement Type Pile in Concrete:-
- Under reamed piles with hand operated tools
- Cast in place bore piles
- Precast prebored piles
Classification of Pile :
A Pile may be classified based on following criteria:
01. Classified Based on Material:-
- Timber pile
- Steel pile
- Concrete pile
- Composite pile
In India concrete pile is the most commonly used material for pile foundation.
02. Classified Based on Shape:-
- Cylindrical pile
- Tapered pile
- Under-reamed pile
03. Classified Based on Load Transfer Mode:-
- End bearing pile
- Friction pile
04. Classified Based on Construction Method:-
- Cast-in-situ reinforced concrete
- Precast reinforced concrete
05. Classified Based on Installation Method:-
- Bored pile
- Driven pile
- Vibrated pile
Thus piles offer a very good solution, where the soil is poor or in the area nearer the seashore.