Geology Reference
In-Depth Information
Figure 5.28
Relationship
between phi
(dynamic) and rate
of loading. The
higher the rate of
application of load
(frequency), the
greater the initial
strength. Data from
Hencher (1977,
1981a).
40 °
φ p
30
°
2.0
3.0
'Loading rate'
Higher stress change,
higher rate of loading
be used for calculating displacements. Recent work con
rms low slid-
ing friction angles post-failure (Lee et al., 2010).
5.8 Rock-soil mixes
It has long been recognised that mixes of soil and rock, such as
illustrated in Figure 5.29, can often stand safely at steeper angles
than if the slope were comprised only of the soil fraction. From
testing on soils together with theoretical studies, the point at which
the hard inclusions start to have a strengthening effect is about 30%by
volume.
Figure 5.29
Cutting through
boulder colluvium.
East of Cape Town,
South Africa.
 
 
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