Control of Settlement Affected Excavation by TBM-EPB with ADECO-RS Approach in Urban Area using Numerical Analysis A Case Study: Qom Subway Line A

Qom Subway line A project has been excavated by an Earth Pressure Balance (EPB) machine. New Excavation Method has been introduced which is based on controlled core-face Tunnel, indeed Controlled Deformation Rocks and Soils (ADECO-RS) in Tunnel. Numerical Simulations are used to Predict Surface Settlement for the Qom tunnel by TBM-EPB with Approach ADECO-RS and without Considering it. The longitudinal and transverse and Contour surface settlements obtained by numerical analyses are compared with Each other. The obtained numerical results for Excavation with TBM-EPB have been confirmed by the monitoring data using the installed instruments on site.

In this study, the Flac3D software has been employed for carrying out 3D numerical modeling of Control settlement. In addition, the Mohr-Coulomb criterion has been considered for geo-mechanical behavior of soil material surrounding the tunnel. the results of numerical models have been verified by the data obtained from monitoring instruments installed in the site.

The numerical results have shown that the maximum transverse surface settlement of Excavation by TBM-EPB with Approach ADECO-RS is around 50% of the maximum surface settlement of the Excavation by TBM-EPB, In addition longitudinal Profiles shown that maximum surface settlement Excavation by TBM-EPB with Approach ADECO-RS occurred about 15m behind face of the tunnel, leads to a decrease of 7.5m in the surface settlement without Approach ADECO-RS. The results have shown control core-face leads to control surface settlement and the Approach ADECO-RS can be used for Control of surface settlement trough induced by tunneling in the similar ground and excavation conditions as Qom subway tunnels.