5) Shear strength of soils

Question 1

Definition of the shear strength of a soil?

Answer 1

Resistance to shearing stress

- its a measure of soil resistance to deformation by continuous displacement of its individual particles.

Question 2

What does shear strength depend mainly on?

Answer 2

Interaction between particles

Question 3

Shear strength of soil derives from 2 components?

Answer 3

Cohesion - (stress indep)

Frictional resistance - (stress dep)

Question 4

These shear strength components depend on…?

Answer 4

• Initial state of the soil (density, OC)

- type of loading (drained/undrained

Question 5

Which are the fundamental parameters?

Answer 5

Effective strength parameters c’ phi’

Question 6

2 lab tests to find shear strength parameters?

Answer 6

1) Direct shear test/simple shear test

2) Triaxial test

Question 7

During a direct shear box test, what does the peak strength correspond with?

Answer 7

Maximum dialation rate

Question 8

During a direct shear box test, when does the ultimate strength occur?

Answer 8

When shearing at constant volume

Question 9

Drained conditions are always assumed for what type of materials?

Answer 9

Sands and gravels, high permeabilities prevent build up of pore pressure.