Effect of Load Bearing Proportion on Mechanical Properties of Shield Tunnel Segments in Fire

Abstract:

A thermo-mechanical coupling numerical model is established for the metro segments under different boundary conditions， and the deformation and internal force of the lining segments at different loads and high temperatures are analyzed by adopting the sequential coupled thermo-stress analysis method. The model was verified by fire test data. Loading bear proportion is a key factor affecting deformation characteristics of segments at elevated temperatures. When the load increases， the mid-span displacement of segments develops more quickly during the heating stage， while the ultimate compressive stress of the concrete at the lower edge decreases. For different boundary conditions of support， the lining segments also have different mechanical behaviors affected by elevated temperatures. When the horizontal displacements at both ends of the lining segments are constrained， due to the non-negligible deformation of the lining segments during the heating process， the bearing reaction force first increases， then decreases， and finally continues to increase until the end of heating.

Key words:fire;shield tunnel segment;loading bear proportion;mechanical property