Shear Strength

Shear Strength:

The strength of a material is the greatest stress it can sustain

The safety of any geotecchnical structure is dependent on the strength of the soil

If the soil fails, the struc ture founded on it can collapse

Thus shear strength is 'The capacity of a material to resist the internal and external forces which slide past each other'

1 Significance of Sh ear Strength:

Engineers must understand the nature of shearing resistance in order to analyze soil stability problems such as;

Bearing capacity Slope stability

Lateral earth pressure o n earth-retaining structures Pavement

Thus shear strength of soil is 'The capacity of a soil to resist the internal and external forces which slide past each other'

2 Shear Strength in Soils:

The shear strength of a s oil is its resistance to shearing stresses.

It is a measure of the soil resistance to deformation by continuous displacement of its individual soil particles.

Shear strength in soils depends primarily on interactions between particles.

Shear failure occurs wh en the stresses between the particles are such that they slide or roll past each other

3 Components of s hear strength of soils

Soil derives its shear strength from two sources:

- Cohesion betwe en particles (stress independent component)

Cementation between sand grains

Electrostatic attraction between clay particles

- Frictional resist ance and interlocking between particles (stress dependent component)