GEOMECHANICS

If the volume of the soil decreases as a result of a change in effective stress, we have

• Positive vol. strain
• Negative vol. strain
• It depends on the geomaterial

The effective stress can be computed by knowing…

• Total stress and pw
• Total stress, pw and bulk moduli
• It depends on the geomaterial

When the total stress path (TSP) and effective stress path (ESP) can be parallel?

• If the process is drained
• Always
• Never

Which is the main feature of an oedometer test?

• The horizontal stresses are zero
• The horizontal strains are prevented
• The volumetric strain is zero

For drawing the effective stress path of an undrained process it is necessary

• To know the volumetric strain
• To measure or estimate pw
• To measure the axial displacements

The general procedure for performing a triaxial test involves the following steps, in order:

• Saturation, isotropic consolidation and shearing
• Saturation, shearing and isotropic consolidation
• Shearing

Performing a CTC test implies a total stress path during shearing with:

• Only change of axial stress
• Only change of radial stress
• Change of axial and radial stresses

If the shearing phase of a saturated specimen is undrained we have

• Variation of void ratio and a constant pw
• Variation of pw and a constant void ratio
• Variation of pw and of void ratio

For a NC soil the in-situ horiz. effective stress depends on

• Vertical total stress, pw and stress history
• Vertical effective stress
• Only the characteristics of the geomaterial

For an OC soil the in-situ horiz. effective stress depends on

• Vertical total stress, pw and stress history
• Vertical effective stress
• Only the characteristics of the geomaterial