The ultimate bearing capacity refers to the maximum carrying potential per unit area of the foundation soil prior to foundation instability, which is an important index for foundation design and foundation stability evaluation.
Where foundations rest on rock, it is appropriate to take into consideration certain other significant parameters such as the geologic characteristics, type of rock and its quality measured as RQD.
A foundation can transmit loads directly to the underlying soil.
If the soil near the surface can adequately support the structural loads, it is possible to use shallow foundations (Craig, 2004).
The ultimate bearing capacity refers to the maximum carrying potential per unit area of the foundation soil prior to foundation instability, which is an important index for foundation design and foundation stability evaluation.
Determining bearing capacity of shallow foundations has always been one of the most important research topics in the field of geotechnical engineering.
The bearing capacity is affected by many factors, such as the characteristics
of the soil, foundation depth and foundation shape, it is difficult and complicated to estimate ultimate bearing capacity.
Therefore, this topic has attracted many researchers’ attention in the past century.
Prandtl (1921) and Reissner (1924) firstly proposed the ultimate bearing capacity calculation theories based on the limit equilibrium method. However, they ignored the weight of the soil and the friction between the foundation and soil.
Terzaghi (1943) was the first to propose a generic equation for estimating U. bearing capacity of shallow foundations, applied to a strip footing with vertical central load, as shown in Eq.