An original soil mixing treatment was chosen to improve the foundation performance of three existing buildings founded on isolated shallow footings and affected by severe damages caused by differential settlements. The settlements were due to the variable presence of a thick manmade ground layer overlaying a layer of alteration of the basal marly-arenaceous Flysch. Thanks to a specifically developed mixing tool with controlled variable diameter, it was possible to drill small holes in the plinths of the existing shallow foundations and to realize beneath them, larger diameter soil mixed bearing columns in direct contact with the existing structures. The tool final shape, the feasibility and the working parameter of the treatment were selected according to the results obtained in specific field trials. The results of the field trials and the outcomes of specific QC/QA procedures employed during the works are also presented.
Subjects: Ground improvement, soil mixing, differential settlements, existing buildings
Author: Massimo Grisolia, Ignazio P. Marzano, Giuseppe Iorio, Raffaele Papa and Giuseppe Panetta
Publisher: DFI, EFFC