Blasting - Rock Slope Engineering: Civil and Mining - page 263

100

60

40

20

10

6

4

2

1

0.6

0.4

0.2

Figure 11.16 Peak particle
velocities produced by construction
machinery compared to explosive
charge (adapted from Wiss, 1981).

0.1

1 2 4 6 8 10 20 40 60 100

Distance (m)

two body waves propagated within the rock is a
compressive, or P , wave, while the slower type
is a shear, or S , wave. The surface wave, or R
wave is slower than either the P or S wave; it is
named after Raleigh who proved its existence. In
terms of vibration damage, the R wave is the most
important since it propagates along the ground
surface, and because its amplitude decays more
slowly with distance traveled than the P or S
waves.
The wide variations in geometric and geolo-
gical conditions on typical blasting sites preclude

the solution of ground vibration magnitudes by
means of elastodynamic equations. Therefore,
the most reliable predictions are given by empir-
ical relationships developed from observations of
actual blasts.
Of the three most easily measured properties
of the stress waves, that is, acceleration, velo-
city and displacement, it is generally agreed that
velocity can be most readily correlated with dam-
age to structures. The stress wave has three
components—vertical, horizontal and radial, and
it is necessary to measure all three components