Laboratory Tests - Rock Mechanics Based on an Anisotropic Jointed Rock Model - page 412

Figure 14.4 Stress-strain curves and determination of the elastic constants of an isotropic
intact rock (DGGT 2004b)

The stress increment F and the

cross-sectional area A of the specimen's ends. The area A may be determined with the
aid of the mean initial diameter

Δσ is calculated from the measured force increment Δ

of the specimen obtained from caliper measure-

ments (DGGT 2004b):

(14.16)

To assess the elastic behavior of intact rock the reversible strains must be separated
from irreversible strains. This requires a test procedure including loading and unloading