Download Slope stability analysis of tailings dam embankments

Survey
yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Document related concepts
no text concepts found
Transcript
Varying bulk unit weight in drained conditions
16
14
Factor of safety
12
10
1V:20H (2.9°)
8
1V:2H (26.6°)
6
10V:1H (84.3°)
4
2
0
0
5
10
|
water
15
20
|
dense mixed grain sand
25
|
concrete
Bulk unit weight γ (kN/m3)
Figure 6.10: Varying bulk unit weight in drained conditions
A zero unit weight suggests the soil is made only of voids which is not possible. The other
end of the scale shows a bulk unit weight which is close to the bulk unit weight of concrete.
For drained conditions, the bulk unit weight does not have an effect on the factor of safety;
however a shallow slope (2.9°) gives a factor of safety that is over 130 times higher than a
factor of safety for a steep embankment (84.3°) (in this case).
Considering an embankment with weight W and slope angle β, the embankment is in
equilibrium when the sliding forces are equal to the restraining forces divided by a factor of
safety (Smith, 2014), i.e.:
𝑊 cos 𝛽 tan 𝜙′
𝐹
tan 𝜙′
𝐹=
tan 𝛽
𝑊 sin 𝛽 =
6.3
This shows that the weight of the material has no effect on the factor of safety or stability or
the embankment, however the bulk unit weight does indirectly effect the values of undrained
cohesion or angle of shearing resistance (higher values of bulk unit weight will have relative
high values of shear strength parameters).
76