ABSTRACT
The use of two-component grout to fill the annular void with a hard rock TBM is becoming more and more common. This is because of the two-component system, made up of a cement grout (Component A) and an accelerator (Component B), presents several technical and operative advantages. Compared with its use on EPBs or Slurry Shields, two-components grout application on hard rock TBMs presents several differences, the main one being the absence of a counter-pressure at the tunnel face. The grout mix-design must be specifically formulated and applied on the TBM taking into consideration these variations from the norm. The example of Saint-Martin-La-Porte job-site at Lyon-Turin project is presented: discussing the technical characteristics of the two-component system, this paper presents the solutions made at the job-site to prepare and test the grout and to optimize the injection procedures for proper back-filling injection through difficult geo-mechanic and hydrogeological conditions.
