Load characteristics study with a multi-coupling dynamic model for TBM supporting system based on a field strain test

A multi-coupling dynamic model for the Tunnel Boring Machine (TBM)’s main support system was established with consideration of the open-type TBM closed chain support form and the multi degree of freedom (DOF) coupling relation. A multi-position dynamic strain test was carried out based on practical engineering. By using the data as a mark of the dynamic load at key parts of the system, the dynamic model was calibrated. Compared with the measured data, the error of the calculated strain values was less than 25%. The results calculated by this model show that the load of the system presents the characteristics of low frequency and periodicity. The transfer law of the load along the main structure was revealed, and the shield support and main thrust cylinder were determined as the main supporting parts that affected the unbalanced load of the key parts of the support system. The influence of the main support on the dynamic load of the main support structure was studied. This study provides a basis for the system's damage-resistant structural design and evaluation of the TBM performance in tunnel construction.