Shear strength of soil Flashcards
Define shear strength
The internal resistance per unit area that the soil mass can offer to resist failure
What is the first of the 3 components of the shear resistance of a soil?
1) Structural resistance to the displacement due to interlocking particles
What is the second of the 3 components of the shear resistance of a soil?
The frictional resistance to translocation between the individual soil particles at their contact point
What is the third of the 3 components of the shear resistance of a soil?
Cohesion or adhesion between the surface of soil particles
Why must we know the shear strength of soil?
To analyse soil stability problems
Name the 4 main problems shear strength failure causes
Bearing capacity
Slope stability
Lateral earth pressure
pavement
What are the 3 factors affecting shearing strength?
Soil composition
Initial state
Structure
What are the parameters of shear strength?
Friction angle and cohesion
What does the Mohr-Coulomb failure criteria theory state?
A material fails because of a critical combination of normal and shear stress and not due to a maximum of either alone
What is the equation gives us the relationship between normal and shear stress
Ο = π + πtanβ
What does Ο stand for with units?
Shear stress kN/m^2
What does π stand for with units?
Cohesion kN/m^2
What does π stand for with units?
Normal/compressive strength kN/m^2
What do Mohr circles show?
The stress or strain state within a plane
π(normal stress0 equation
= normal force/ area of cross section of the sample
