ABSTRACT
Expansive geopolymers, such as Geobear Geopolymers (GPs), are usually injected post damage in weak surficial layers to re-level shallow formations. In contrast to conventional applications, GPs could also be used in a proactive real time environment to provide asset protection during deep excavation/tunneling. A field trial comprising GP injections at different depths was carried out in one of Thames Tideway West main worksites to assess their actual interaction with competent ground and especially London Clay. Fibre Bragg Grating (FBG) Fibre Optic Sensing (FOS) cables were installed in collaboration with Cambridge Centre for Smart Infrastructure and Construction to monitor the injections. The GPs expanded approximately 2 times their initial volume in London Clay, nevertheless further trials are required for the development of real time deep injections applications. The FOS system captured satisfactorily the induced strains and can therefore be considered a reliable tool for underground real time applications.
