Difference between Shallow and Deep Foundation

Foundation is defined as that part of the structure that connects and transmits the load from the structure to the ground soil. The foundation transmits the load of the structure and it’s self-weight to the soil such that the ultimate bearing capacity of the soil is not exceeded and the settlement is tolerable.

 Foundation can be mainly categorized into 2 categories, Deep Foundation and Shallow Foundation. They’re primarily categorized on the basis of the extent or depth whereupon foundation is offered.

Shallow Foundation: Shallow foundation are those foundations in which the depth at which the foundation is placed is less than the width of the foundation (D < B). Shallow foundations are generally termed as spread footing as they transmit the load of the super structure laterally into the ground.

Deep Foundation : Foundation which is placed at a greater depth or transfers the loads to deep strata is called deep foundation.

Sources	Shallow Foundation	Deep Foundation
The depth of foundation	The depth of the shallow foundation is usually about 3 m or less than the footing.	Greater than shallow foundation.
Cost	Shallow foundation is cheaper.	Deep foundations are usually more expensive than shallow foundations.
Feasibility	Shallow foundations are easier to construct.	The construction process of a deep foundation is more complex.
Mechanism of load transfer	Shallow foundations transfer loads mostly by end bearing.	Deep foundations rely on both bearings and friction, with some exceptions, such as piles.
Advantages	Building materials are available, less labor is needed, the construction procedure is simple and affordable.	The foundation can be provided to a greater depth, provides lateral support and is resistant to uplift, effective when the foundation is shallow, can support a huge load, etc.
problem	Possibility of compaction, generally applicable for light structure, low resistance to lateral loads, etc.	More expensive, requires skilled work, a complex construction procedure, can take a long time and some types of deep foundations are not very flexible, etc.
Types	Isolated foundation, strip foundation, mat foundation, combined foundation etc.	Pier foundation, pile foundation, caissons