Lining stresses in a TBM-driven tunnel: A comparison between numerical results and monitoring data

The paper deals with the evaluation of lining forces in TBM-driven tunnels in clayey soils. A 3D numerical model has been developed accounting for the main features of the excavation and construction, such as front pressure, cutterhead overcut, shield conicity, lining installation inside the shield, tail void grouting, grout hardening and injection distance from the shield. To accurately simulate the soil-shield and the soil-grout-lining interaction processes associated with the gap closure, the algorithm works in large-strain mode, thus updating the grid nodes position after each calculation step. A comparison between numerical results and monitoring data recorded during the construction of a hydraulic tunnel in fine-grained soils is presented. The collected data show the evolution of the lining forces due to the advancement of the excavation in undrained conditions and during the subsequent consolidation process. The results confirm the effectiveness of the proposed numerical approach as a design or analysis tool.