Before construction, theodolite is used to measure and place the pile position by
polar coordinate method, and steelhead or wooden pile is inserted into the center of
the measured pile position as a sign. The error of pile position measurement is
controlled within 1 cm. When the pile machine is installed in place, the chassis of
the machine frame should be flat and stable on the ground. The machine base
should be adjusted horizontally and the machine frame should be vertical. The
instrument should be used to check and correct the chassis so as to meet the
requirement that the deviation of drilling verticality is not more than 1%. The
deviation between the center point of steel casing and the center point of pile is not
more than 20 mm. During construction, the air compressor is started first, and when
the air pressure reaches a certain value, the drilling rig’s internal and external power
heads are started for impact drilling. The speed is generally controlled at 17 r=min
Fig. 11.44 Sketch map of construction process of large diameter pneumatic DTH hammer drill
Table 11.13 Equipment name and model parameters
Name of device
Model and specification
Unit
Amount
Engineering rig
150PW
Set
1
Air compressor
LUY238D
Set
2
Steel bar cutter
GQ-4
Set
1
Crawler crane
50T
Set
1
Excavating machinery
120
Set
1
Steel sleeve
600*1 000 mm
Meter
300
Concrete conduit
250 mm
Meter
30
Plug-in vibrator
/50
Set
1
Vibration hammer
60
Set
1
Initial irrigation bucket
1.5M3
Piece
1
11.6 Typical Engineering Cases
263