Published August 31st 2019
As part of the next phase of this ‘New Town’ development in the East of England, the main contractor needed to install the next section of 450mm concrete drainage. The drainage, to be installed into the underlying Clay at circa 5 mbgl was well into the groundwater, located within the overlying River Terrace Gravels. The solution proposed by Project Dewatering Ltd (PDL) was to install 350 well-points on a double sided configuration, either side of the drainage excavation. The well-points were installed from a reduced level to reduce costs and accelerate the installation process. The well points were installed by a conventional jetting process and were connected to header main and then pumped by a diesel vacuum pump. Using this system PDL successfully lowered the groundwater level from 2.0 m to 5.0 m below the surface, to enable the successful installation of the new 450mmØ concrete drainage run. Discharged water was pumped into a V notch tank which will allow visual inspection and sampling of the water prior to disposal to soakaway.