Vinci BAM Nuttall JV
DAWSON-WAM was contracted by Vinci BAM Nuttall JV to construct a new secant wall entrance to Victoria Station as part of their upgrade works to one of the busiest transport interchanges in London.
In all over 150lm of 750mm diameter hard/hard secant walls were installed with piles ranging in length between 12 and 15m. Piles were installed to very strict vertical tolerances of over 1:200, and this was ensured by the use of DAWSON-WAM’s Cased CFA system to install the piles.
Steel reinforcing was also set to very high tolerances as pile reinforcement contained starter packs which allowed easy connection of intermediate slab levels to the secant wall and these had to be set very precisely controlling the orientation of the reinforcing and the level at all times. The top of the steel reinforcement was to be placed over 4m below existing ground level and this was closely controlled by the installation of steel reinforcement using a plunge system installed on a second leader rig.
To make things more complicated piles were installed 1m above the existing Victoria Underground Line under very tight controls from Vinci BAM Nuttall and London Underground.
All the works were completed in very tight site conditions in close proximity to noise and vibration sensitive neighbours.
As part of the contract, 12no. 750mm diameter load bearing piles were installed as well as 100lm of steel sheet piling over 2 phases adjacent to live roadways.