Correct Answer - Option 1 : 97.63 kPa
Concept:
Coulomb's equation,
τ = C + σn tan ϕ
Where,
τ = Shear strength of soil
C = Apparent cohesion
σn = Normal stress on the plane of rupture
ϕ = Angle of internal friction
Calculation:
Given,
C = 80 kPa, σn = 100 kPa, ϕ = 10°
τ = C + σn tan ϕ
τ = 80 + 100 tan 10°
τ = 97.63 kPa.