Question

Limitations of terzaghi's bearing capacity equation

Answer 1

Based on the  terzaghi's bearing capacity theory the column of the load p will be store to the stress of an edges due to the 3 zones to foot the overburden pressure q(=gD) on the footing.  

Therefore the first term will be related to the cohesion on the soil. And the second term will be depth on the footing to an overburden pressure .

Strip footings

Qu = c Nc + g D Nq + 0.5 g B Ng  

Square footings

Qu = 1.3 c Nc + g D Nq + 0.4 g B Ng  

Circular footings

Qu = 1.3 c Nc + g D Nq + 0.3 g B Ng