Environmental considerations 205
PPV
K E
r
G
in mm s
=
/
(6.4)
where:
K is the factor evaluated by field vibration measurements
r is the distance from vibrator in m
From Figure 6.2, for a building at a distance of 6 m from the vibrator
position of the S-vibrator, we get a PPV G of 13 mm/s and for the M-vibrator
6 mm/s, when assuming a 50% (exceeding) probability. The corresponding
ground PPAs (PPA G ) follow from Equation 6.2 with 2.5 m/s 2 for the 30 Hz
S-vibrator and 1.9 m/s 2 for the M-vibrator, operating at 50 Hz, both values being well below the 0.3–0.5 g threshold. When considering, more
appropriately, a probability of 2.25% (exceeding) only, PPA values rise to
6.6 m/s 2 for the S-vibrator and to 5.3 m/s 2 for the M-vibrator, which both
are in excess of the above limit. Should the structure be founded on loose
to medium dense, saturated sand, the resulting accelerations are marginally within acceptable limits for the M-vibrator at the 6 m distance but are
not tolerable should the S-vibrator be used, since it could result in intolerable induced settlements of the structure. Based upon a tolerable ground
PPA value of 0.5 g, the necessary distance from the building, not to cause
vibration-induced settlements to it, should be about 8 m for this more
powerful vibrator. When the influence of other types of depth vibrators
are concerned, their vibratory energy E can be calculated using the data
from Table 3.1 allowing a sensible comparison with the results as given in
Figure 6.2.
Achmus et al. have developed from these data a risk assessment method
for potential building damage resulting from the impact of the vibratory
deep compaction.
Distance r (m)
M – vibrator
E = 1 kNm
S – vibrator
E = 4 kNm
P = 50%
P = 2.25%
PPV
G (mm/s)
0.1
1
10
100
100
10
1
Figure 6.2 Ground PPV values induced by Keller M- and S-vibrators for 50% and
2.25% probabilities. (Redrawn from Achmus, M. et al., Untersuchung zu
Bauwerks—und Bodenerschütterungen infolge Tiefenrüttlung, in 3. Hans
Lorenz Symposium, Grundbauinstitut H. 41, TU Berlin, Germany, 2007.)
PPV
K E
r
G
in mm s
=
/
(6.4)
where:
K is the factor evaluated by field vibration measurements
r is the distance from vibrator in m
From Figure 6.2, for a building at a distance of 6 m from the vibrator
position of the S-vibrator, we get a PPV G of 13 mm/s and for the M-vibrator
6 mm/s, when assuming a 50% (exceeding) probability. The corresponding
ground PPAs (PPA G ) follow from Equation 6.2 with 2.5 m/s 2 for the 30 Hz
S-vibrator and 1.9 m/s 2 for the M-vibrator, operating at 50 Hz, both values being well below the 0.3–0.5 g threshold. When considering, more
appropriately, a probability of 2.25% (exceeding) only, PPA values rise to
6.6 m/s 2 for the S-vibrator and to 5.3 m/s 2 for the M-vibrator, which both
are in excess of the above limit. Should the structure be founded on loose
to medium dense, saturated sand, the resulting accelerations are marginally within acceptable limits for the M-vibrator at the 6 m distance but are
not tolerable should the S-vibrator be used, since it could result in intolerable induced settlements of the structure. Based upon a tolerable ground
PPA value of 0.5 g, the necessary distance from the building, not to cause
vibration-induced settlements to it, should be about 8 m for this more
powerful vibrator. When the influence of other types of depth vibrators
are concerned, their vibratory energy E can be calculated using the data
from Table 3.1 allowing a sensible comparison with the results as given in
Figure 6.2.
Achmus et al. have developed from these data a risk assessment method
for potential building damage resulting from the impact of the vibratory
deep compaction.
Distance r (m)
M – vibrator
E = 1 kNm
S – vibrator
E = 4 kNm
P = 50%
P = 2.25%
PPV
G (mm/s)
0.1
1
10
100
100
10
1
Figure 6.2 Ground PPV values induced by Keller M- and S-vibrators for 50% and
2.25% probabilities. (Redrawn from Achmus, M. et al., Untersuchung zu
Bauwerks—und Bodenerschütterungen infolge Tiefenrüttlung, in 3. Hans
Lorenz Symposium, Grundbauinstitut H. 41, TU Berlin, Germany, 2007.)