Waste Rock Behavior at High Pressures: Dimensioning High Waste Rock Dumps - Multiscale Geomechanics: From Soil to Engineering Projects - page 97

4.4.4.4. Deformation modulus

The results obtained from the different waste rocks analyzed were used to
establish stress-strain relations, presented in Table 4.5.

In particular, the hyperbolic model was used to determine the secant modulus
representative of deformations of about 10 -3 , through the initial tangent modulus
deduced from the adjustment of the hyperbole, as well as its evolution with the
confining pressure [BIA 93].

q (kg/cm 2 )

q (x 0.1 MPa)

50

40

Test

Hyperbolic
adjustment

30

20

10

0

0 5 10 15 20

ε 1 (%)

n

'
3


=⋅ ⋅  

σ

Ek P P

th a

a

where:

k: modulus factor;

Pa: atmospheric pressure (0.1 MPa);

σ' 3 : effective confinement stress; and

n: power.

Materials k n

ROM waste rock, homothetic grain size distribution 170 0.43

Leached waste rock, homothetic grain size distribution 120 0.51

Leached waste rock, scalped grain size distribution 90 0.81

Table 4.5. Deformation moduli deduced from the hyperbolic adjustment