Project Dewatering has successfully undertaken groundwater control operations on projects such as:
HMB Alliance 2004-2005
The installation of vacuum wellpoint dewatering systems to enable construction of 2no Primary Settlement Tanks, Clarifier and UV Plant together with associated pipework for works improvements. Predominantly silty sands in a tidal zone of the adjacent River Ribble. Wellpoints sanded in with water flush jetting methods. Geho ZD900 piston-type dewatering pumps used successfully throughout.
Green Lane UID – Derby
Vinci Construction 2008-2009
To enable construction of culver connection (in-take & off-take) in open-cut excavation. Installation of perimeter vacuum wellpoint system in River Trent Terrace Sand & Gravels. Wellpoints connected by header main to 150mm Ø silenced diesel vacuum dewatering pumps.
Belfast Sewers Project – Belfast
Farrans/Morgan Est JV 2006-2009
Deep Wells using submersible 415V borehole pumps were used as part of the successful dewatering on the Belfast Sewer Project which involved extensive tunnelling from 28 shafts. Project Dewatering Limited undertook dewatering installation at 18no shaft locations across the city with deep wells drilled using rotary and cable percussive methods up to 60m deep.
Cog Moor STW – Glamorgan
Deep Well dewatering of 2no FST tanks at Cog Moor WwTW in Barry. High fissure flow in the Coal Measures has been dewatered using 13no deep wells around the cofferdam perimeter. The 415V (7.5 kW) pumping system yielded upto 600 m3/hour to enable groundworks upto 8.0m deep to be undertaken in dry and stable conditions.
RAF Kinloss – Grampian
AMEC 2005 – 2006
Surface Water Treatment Project required single and double-sided vacuum wellpoint systems. Geho ZD900 piston-type dewatering pumps used successfully throughout placement of over 900 lin.m of pipeline. Wellpoints sanded in with water flush jetting methods with the dewatering system ‘leap-frogged’ along as pipeline installation progressed.
Second Tyne Tunnel Crossing
Bouygues Travaux Publics UK 2009-2010
Various works including pumping tests, deep well dewatering water for northern diaphragm wall approach structure and ejector wells for southern SCL sections. Project Dewatering undertook the design, installation and hire of dewatering systems. Wells drilled using cable percussive drilling techniques in variable ground conditions either side of the River Tyne.
CTRL 230 – Stratford Box
Skanska UKCL 2001-2004
The Stratford Box is the main international station for the CTRL in East London. It consists of 1075m long x 25m seep diaphragm wall cofferdam. Project Dewatering oversaw the drilling and installation of 22no x 65m deep wells and associated piezometers as part of a permanent dewatering system with a 120 year design life. The well and control specification was to a very high standard and carried out QA scheme specific to the works. The project involved acidization development of the Chalk, 5 day pumping tests on each well, together with a sophisticated monitoring and telemetry alarm system.
Victoria Square – Belfast
Farrans Construction 2004-2007
To enable construction of a 20,000 m2 x 9m deep basement (car park) for a city centre retail unit. Project Dewatering Limited installed 17no x 50m deep wells using rotary drilling methods to reduce and maintain the sub-artesian head within the Sherwood Sandstone to below excavation level. The job also included the installation of a number of monitoring piezometers and recharge wells. This is the largest single dewatering operation undertaken in the Northern Ireland and pumped continuously for over 2 years.
12.5mØ Shaft – Walton Le Dale
HMB Alliance 2004
Project Dewatering Limited was responsible for the design, installation and management for the dewatering requirements on this 12.5m Ø x 16.0m deep shaft, constructed using open-face segmented rings. With permeability < 4 x 10-5 m/sec we installed a total of 18no ejectors wells, which generated stable and dry working conditions throughout the contract.
8A Holland Villas Road. London W11
Thames & Newcastle Limited 2003
For the construction of a basement below the foot-print of a Grade II listed building. Project Dewatering Limited installed a number of internal deep wells using a cut-down cable percussive drilling method. The wells were pumped using a 240V manifold system.
A485 – Pontarsais
Alun Griffiths Contractors Limited 2000
To create the stability of clays laminated with fine sands along a road embankment on the A485 in Pontarsais in Wales, Project Dewatering installed seven deep wells and sand drains.
The Vineyards Office Complex - Uxbridge
Shepherd Construction 2001
To depressurise the excessive pore water pressures within the London Clay within a Secant Pile Cofferdam in Uxbridge, Project Dewatering installed 56 ejector wells within the cofferdam.
Dartford STW – Essex
Costain Limited 1999
The Dartford Project required the installation of twelve deep wells within the Chalk close to the River Thames, to allow the open-cut construction of four Final Settlement Tanks and a pumping station.