Difference Between Shallow and Deep Foundation

• Foundations are defined as a substructure element which is used to transfer the heavy superstructure loads to the soil in such a way that neither the surrounding soil is stressed in excess of allowable stress of soil nor it undergoes deflection more than permissible deflection.
• Foundations are broadly classified of two types:-
• Shallow Foundation 
• Deep Foundation

Difference between Shallow and Deep Foundation

• For a Shallow foundation, the depth of foundation is equal to or less than its width. Whereas for Deep foundation, the depth of footing is equal to or greater than its depth.
• A shallow foundation is located at very low depth, whereas a deep foundation is constructed at more depth.
• In case of Shallow foundation, loads are primarily supported by the action of end bearing. Whereas for Deep foundation, loads are supported partly by frictional resistance around the surface and partly by bearing at the base of foundation.
• The construction of shallow foundation is done in open excavation. Whereas the construction of deep foundation is generally carried by boring or drilling well beneath the ground. This will lead to a better visual inspection in case of a shallow foundation over deep foundation.
• Shallow foundation are in general cheaper than deep foundation in construction. Deep foundation requires more machinery and more technicality which increases the costs.
• Allowable load in case of shallow foundation is way less in comparison of deep foundation. So, for heavy superstructure construction, Deep foundation is always preferred over shallow foundation.
• Lateral effect of soil is better resisted by the deep foundation in comparison to that of shallow foundation.
• Shallow foundation requires less labour in comparison to that of deep foundation. Deep foundation even requires skilled labour.
• Shallow foundation is not suitable for soils which are weak in upper stratum. In this scenario Deep foundation is preferred over shallow foundation.

Difference between Shallow and Deep foundation