Grouting has a long history in tunnel and shaft construction and emphasises sealing or consolidating weak or water-bearing ground conditions. Organic grouting is mainly carried out within complex ground conditions or areas of heavy water inflow. However, standard
grouting equipment is limited to cement-based grout mixes or organic materials since these materials demand different equipment and grouting criteria.
With recent developments in grouting technology, both grouting materials can be utilised in various ways - either individually or with different mixing ratios depending on the objective
of the grouting works. The unique system's advantages are apparent when used to stop water inflow. Polyurethane resins accelerate the adhesion and hardening process of the cementbased grout, thus significantly reducing the dispersion of the grout mix in groundwater.
This technology has been dubbed Hybrid Grouting (combined Cement-Polyurethane Grout Mix) because it garners both the advantages of economical cement-based grouting and the advantages of highly reactive resin injections. Furthermore, the processes of combined
cement-polyurethane grouting are carried out fully automated. Therefore, the usage of combined cement-polyurethane grouting enables controlled and efficient grouting operations in tunnel and shaft construction.
The paper explains the equipment and the technology of combined cement-polyurethane grouting. The system's effect and intensity are demonstrated by reviewing various actual grouting works.