UK CONTRACTOR Penine Vibropiling has just finished its first bottom-feed vibro replacement contract in central France.
Virgil, the nickname for one of the company's latest multi-purpose rigs for vibro replacement and vibroconcrete column installation, was used to install over 2,000 bottom-feed stone columns down to depths of 8m for a new Geant hypermarket at Chalone-sur-Saone, south of Dijon.
The joint venture contract with French geotechnical contractor Menard was to treat fill and underlying clayey silts, to allow the construction of the foundations.
The rig is fitted with sophisticated on-board instrumentation that records the depth of the poker and the hydraulic pressure in real time as the stone columns are formed, with results stored on a data logger. Through a link with a laptop computer and a mobile phone, data was relayed to Penine's UK office to check that the columns were being installed to specification.
Further quality control was ensured by subsequent dynamic probing and pressure- meter testing within the treated ground.