Study on Roof Deterioration Characteristics of Immersed Tunnel Exposed to Fire by Multi-Phase Meso-Model

Deterioration characteristics analysis of lining structure has received intense research interests for immersed tube tunnel fire, while a considerable part of the spotlight is on numerical simulation. However, most of existing works consider concrete lining as a macroscopic homogeneous material for simulation analysis, ignoring the difference of its internal components. This paper aims at studying the mesoscopic deterioration characteristics of immersed tube tunnel roof structure towards efficient safety design of immersed tube tunnel roof. In particular, we establish a mesoscopic model of immersed tube tunnel under thermo-mechanical coupling using ANSYS. Compared with the traditional homogeneous approaches, the proposed mesoscopic model can directly simulate the fire degradation process of immersed tube tunnel roof structure, which blazes marvelous trail for related engineering applications. Our extensive simulation results reveal the progressive failure process of micro-cracks initiation, development, expansion and coalescence in the roof of immersed tube tunnel.