Yoshino Hiroki

Post-mortem analysis of Ground behavior around SENS by three-dimensional continuum FEM model

Mitsutaka Sugimoto

　In the construction of an in-situ concrete support system with TBM (hereinafter referred to as SENS), a primary concrete lining is pressurized and filled between the ground and the inner frame to form a tunnel lining continuously. Therefore, the inner frame receives buoyancy continuously due to fresh concrete and the primary lining tends to move upward rigidly. As the time passing, the primary lining is hardened and the earth pressure from the ground acts on it.To estimate this acting earth pressure, it is necessary to estimate the behavior of the inner frame, which changes three-dimensionally and sequentially. Then an analytical model, which can express the interaction among corresponding ground, primary lining, and inner form, is required.
　In the previous research, a three-dimensional model with beam-spring model, which takes into consideration the load condition and the construction process of SENS, was developed and it was verified using the in-site measured data of actual tunnels. Furthermore, to investigate the influence of excavation on the ground movement around the tunnel by a three – dimensional ground continuum model was developed and was examined, comparing the calculated ground movement with the measure one, at a shallow tunnel, where ground movement is expected to occur. As a result, the validity of the proposed model was confirmed.
　In this research, the SENS lining behavior of the Hokkaido Shinkansen Yotei Tunnel, was analyzed by a continuum model to obtain basic knowledge for construction management. As a result, the generality of the proposed analysis method was confirmed.