Backfill grouting research at Groene Hart Tunnel

摘要

Measurements on back-fill grouting at Groene Hart Tunnel (GHT) are described and analysed.The research utilises TBM data, monitored grout pressures and measured rheological properties of tunnellingfluids. Grout injection strategy and vertical grout pressure distribution behind the TBM were found to agreewith established theory, like found in other tunnelling projects. However, on some occasions different smallervertical grout pressure gradients were found, which might have been caused by an incidental upward movementof the tunnel. It is shown that the consolidation of grout determines the decay of grout pressures. The associatednet hydraulic resistance of surrounding soil is substantially higher than according to radial flow theory. Thishigher resistance is attributed to bentonite originating from the face of the TBM, having invaded the grout-soilinterface.