Chapter 7, Problem 7.1QPP

List the three types of bearing capacity failures and explain the differences between them.

To determine

The list of three types of bearing capacity failures and differences between them.

Explanation of Solution

Three types of bearing capacity failures are:

1. General shear failure.
2. Local shear failure.
3. Punching shear failure.

The differences between them are explained in tabular form below:

Serial Number	General shear failure	Local shear failure	Punching shear failure
1.	The continuous, well-defined failure surface	Not well-defined failure surface,	Failure surface is not well defined, no bulging of ground surface adjacent to the foundation
2.	Sudden failure as shown in the load settlement curve.	Not a sudden failure.	Not a sudden failure, failure occurs gradually as depicted in the load-settlement curve.
3.	Dense and stiff clay, incompressible soil	Relatively loose and soft soil	Lose and soft soil, highly compressible soil
4.		Considerable settlement	Lage settlement occurs
5.	Bulging of failure surfaces at ground occurs	Slight bulging of soil around footing is observed	Shearing in vertical direction around the edge of the footing
3.	Tilting of footing occurs	No tilting	No tilting
7.	Relative density $\text{>70}\raisebox{1ex}{$0$}\!\left/ \!\raisebox{-1ex}{$0$}\right.$	Relative density $\left(\text{30}\raisebox{1ex}{$0$}\!\left/ \!\raisebox{-1ex}{$0$}\right.-\text{70}\raisebox{1ex}{$0$}\!\left/ \!\raisebox{-1ex}{$0$}\right.\right)$	Relative density $\text{<30}\raisebox{1ex}{$0$}\!\left/ \!\raisebox{-1ex}{$0$}\right.$