Natural or artificial underground cavities are frequently encountered below historic cities or in particular regions. These cavities can often put at risk the stability of structures; a tried and tested technique for making them safe is to fill them with Laterlite Expanded Clay.
Thanks to its high compressive strength in fact, expanded clay (either loose or bound with cement), enables stresses on the ground to be redistributed throughout the subsoil, eliminating dangerous load concentrations and attenuating and redistributing them over time. As compared to filling with a traditional aggregate, this significantly reduces the additional load and the lateral thrust, avoiding the risk of settlement.
This technique is also used for making safe disused underground tanks, by filling them with expanded clay and leaving them in place.
Tensioning the fill
After a cavity has been filled with expanded clay, the effectiveness of the procedure can be maximised by injecting an expanding polyurethane resin into the cavity, completely saturating the internal volume and applying a predetermined amount of precompression to the cover above the cavity. This resin injection system is denominated “Cavity Filling” and was developed by Laterlite in collaboration with Uretek.