Piling equipment and methods 97resistance curves for a 25 tonne drop hammer with drops of 1.5 or 2.0 m to be used as a standby
to achieve the required soil resistance if this could not be obtained by the diesel hammer.
Vibratory hammers are very effective in loose to medium-dense granular soils and the
high rate of penetration of low-displacement steel piles driven by vibratory hammers may
favour their selection for these conditions.
3.1.7 Noise and vibration control in pile driving
The control of noise in construction sites is a matter of increasing importance in the present
drive to improve environmental conditions, and the Noise at Work Regulations 2005 implement
the latest European Directive for the protection of workers from the risks related to the expo-
sure to noise. The requirements for employers to make an assessment of noise levels and take
action to eliminate and control noise are triggered by three action levels: daily or weekly
(5 days of 8 hours) personal noise exposures of 80 dBA as the lower level, 85 dBA as the upper
level and a peak (single loud noise) of between 135 and 137 dBA. The exposure limitvalues
are 87 and 140 dBA at peak; the method of calculating the various exposure levels is defined
in the Regulations. Employers are required to reduce noise at source to a minimum by using
appropriate working methods and equipment, but if noise levels cannot be controlled below the
upper action level by taking reasonably practicable measures, hearing protectors which eliminate
the risk must be provided. As these Regulations do not apply to control of noise to prevent
annoyance or hazards to the health of the general public outside the place of work, the
Environment Protection Act (EPA) and Control of Pollution Act provide the general statutory
requirements to control noise and vibrations which are considered to be a legal nuisance.
(^100200300400500600)
Driving resistance (blows/250 mm penetration)
0
5
10
15
20
25
Soil resistance to driving (MN)
D.100 Diesel hammer
Required ult. soil resistance
25 tonne drop hammer
2.0m drop
1.5m drop
Figure 3.17Pile driveability curves.