Relating to spread footing foundation design, calculate the value for the soil rigidity index, I r , given the indicated conditions, to use with the extended bearing capacity equation: (a) Soil...

Relating to spread footing foundation design, calculate the value for the soil rigidity index, I_r
, given the indicated conditions, to use with the extended bearing capacity equation:

(a) Soil modulus of elasticity is 25,000 kPa, Poisson’s ratio is 0.42, soil unit weight is 18 kN/m³, shear strength values are cohesion , and the angle of internal friction is 22°. Find I_r
for a point 3 m below the soil surface

(b) The modulus of elasticity is to be estimated from the results of a consolidation test where Cc is 0.35 over the pressure range between 50 and 100 kN/m²
and the value of e0 is 1.40. Poisson’s ratio is 0.30. In place, the soil has a unit weight of 17 kN/m³, a cohesion equal to 60 kN/m², and an angle of internal friction of 15°. Find I_r
for a point 4 m below the soil surface.