2015
contractors’
directory
67
ONSHORE
PIPELINES
OFFSHORE
PIPELINES
TURNKEY
CONSTRUCTION
HORIZONTAL
DIRECTIONAL
DRILLING
COMPRESSOR
STATIONS
WELDING
FINANCE,
STRATEGY
& ANALYSIS
TERMINALS
FEASIBILITY
STUDIES
RESEARCH &
DEVELOPMENT
MAINTENANCE
REHAB
14 sections, of which Hoelscher Wasserbau was awarded
10 sections for the dewatering works. For this project,
the company supplied five deep well drilling rigs, two
wellpoint drilling rigs, four trenchers for the installation of
horizontal dewatering, fifteen 4 x 4 trucks, 10 maintenance
vans, 30 pick-up trucks along with 100 employees. The
company installed over 5000 wellpoints, 95 000 m of
horizontal dewatering and 1600 deep wells to allow dry
and safe excavation of the pipeline. This was the largest
running construction site in Germany that required major
dewatering resources, which Hoelscher Wasserbau
supplied.
Angerlo-Beuningen Pipeline, the Netherlands
As part of the north-south pipeline route, the
Angerlo-Beuningen section was the part with the
most difficult requirements in terms of groundwater
management.
For dealing with the very high permeability,
and as a consequence of high flowrates of pumped
groundwater, a double trenched horizontal pipe
system of 72 000 m was installed. The groundwater
had a high content of iron. To avoid discharging
water with high iron content into channels or rivers,
it was necessary to treat the water in de-ironing
plants. In areas were de-ironing would have been very
expensive, the groundwater was transferred within
a closed system to a re-infiltration system and then
infiltrated back into the aquifer. This was achieved by
using the HW-DSI jet suction infiltration system. In
total, 16 million m³ of groundwater has been rejected
into the ground.
