Roger Bullivant provide the foundations for a new housing development in Walsall comprising of 412 housing plots.
RB developed a programme utilising two foundation techniques: ground improvement vibro stone columns and displacement piling.
A top feed vibro stone column rig and the quiet hammer rig system were used.
Exploratory boreholes revealed the site to be underlain by a variable thickness of made ground over glacial till. The material comprised of medium dense sand or very gravely clay-like medium sub rounded sand.
Vibro stone columns were utilised to help densify the ground of the glacial till.
An isolated area of the site was unsuitable for ground development, as such a piled solution was specified.
A total of 5122 stone columns were installed equating to 412 housing plots to depths ranging from 1.2m – 2.1m. The scheme provides a total baring capacity of 125kN/m2.
Vibro stone columns help densify and stabilise the area whilst the pre-cast displacement piling create supports in the black clay-like regions of the site.
The pre-cast displacement piles amounted to a total of 466, installed to a depth of 10m and designed to provide a baring capacity of 350kN.