The development was for a new regional distribution center with associated hardstanding at the Central Park Bristol development in Avonmouth. 45,000m2 of external reinforced concrete slab area was identified for ground improvement due to the presence of weak underlying alluvium and recently placed made ground.
It was considered that the construction of a ground bearing slab with no soil improvement or replacement would result in unacceptable post construction settlements and deformations. Vibro Menard were tasked with providing a solution for the external slab areas as an alternative to a fully suspended slab on precast driven piles which would reduce post construction settlements to an acceptable level of below 25mm.
The project required a very tight working programme to allow the contractor to construct their drainage and construct the service yard to gain access around the building.
The soils comprised of 1.5 to 2.5m of made ground fill comprising of clayey gravels which had been placed in an uncontrolled manner. This made ground ran over very soft silty clays to depths of 11 to 14m with weathered mudstone / dense gravels below.