Question

Assertion (A): Terzaghi's bearing capacity theory overestimates the bearing capacity of footings.
Reason (R): Terzaghi's theory neglects the shearing resistance of rupture surface in the soil above the foundation level.

• A. both A and R are true and R is the correct explanation of A
  
• B. both A and R are true but R is not a correct explanation of A
• C. A is true but R is false
  
• D. A is false but R is true

Answer 1

The correct option is D A is false but R is true

Terzaghi's theory neglects the shearing resistance of rupture surface in the soil above the foundation level so this theory underestimates the bearing capacity of footing.
Terzaghi considered a continuous footing of width B placed at a depth of D below the ground surface. In the derivation of the equation the following assumptions were made.

• The soil is homogeneous, isotropic and Coulumb's law of shear strength is valid.
• The footing is continuous and has a rough base.
• Failure zone does not extend above the base of the foundation.
• Shear resistance of the soil above the base of the foundation is neglected.
• The soil above the base of the foundation is replaced by a uniform surcharge.
• Principle of superposition holds good.