Comparison of estimated and actual measured face pressure in EPB-TBM tunnelling

Abstract: Tunnel face instability is the most common problem in difficult geotechnical conditions. The evaluation of a suitable face support pressure is a critical element in the design and construction phases of EPB-TBM and Slurry-TBM tunnelling technologies. In this study, measured tunnel face pressure in Dez-Ghomroud transfer tunnel (Lot.1) is compared with the results from analytical methods. This comparison shows that analytical methods overestimate the average required tunnel face support. Analytical methods predict a value that was 1.5-1.7 times higher that measured face pressure.