The initial proposed piling solution being not economically viable, Menard had been tasked to design a ground improvement solution to mitigate risk of differential settlements below the housing plots and associated externals.
After additional SI comprising CPTs and thorough desk study analysis, Menard proposed a combination of Controlled Modulus Columns (CMC) under the ground bearing houses rafts and Vibro Stone Columns (VSC) below the garages rafts and access roads. Both techniques were proposed as partial depth treatment of the made ground in the deep quarry areas. Creep settlements had been assessed on the back of the SI laboratory tests and site historical observation and allowed for in the design.
Collaborative works with the structural engineer to define achievable performance of the infrastructure and with the warranty provider to relax standard performance criteria have been undertaken to reach a cost effective yet robust ground improvement solution.
The use of a VSC and CMC combination in lieu of a dig out and replace with lime and cement stabilisation and piles brought a significant reduction in the overall embodied carbon footprint of the overall project.