Menard proposed to treat the whole site (house plots and associated externals) using the Dynamic Compaction technique in order to homogenise the made ground and ensure long term settlements performance. This solution has been chosen over traditional piles due to the high risk of obstructions within the made ground. It is to be noted that considering the proximity of the nearby properties, vibrations on site and at neighbours’ properties were monitored to ensure PPV threshold were not overpassed during the operation. A long-term zone test over a period of 30 days has been made in order to get the relevant insurances with the NHBC. On top of that, a 10kPa load zone test and 4 additional dummy foundations load tests at 180kPa were performed.
The goal was to achieve qc values of 5MPa between 0 and 5m, 4MPa between 5 and 8m and 3MPa between 8 and 10m. Post-treatment CPT’s have confirmed it was comfortably achieved
The use of Dynamic Compaction significantly reduced the overall carbon footprint as no supply of material was required (neither concrete nor aggregate) and no material had to be removed from site, making DC a very eco-friendly alternative to brownfield remediation.