Simulation Analysis Of Temperature Field And Mechanical Properties Of Immersed Tunnel Joints

In recent years,with the further development and utilization of underground space,underground space structure has been widespread concern,a series of underwater structures came into being,which was undoubtedly the most representative of the immersed tube tunnel.The underwater immersed tunnel has many advantages,but its characteristics such as closed space and few escape routes have become the main reasons for its frequent fire disasters and difficulties in rescue.Due to the narrow and long tunnels and the difficulty in ventilation,the tunnel structure will rapidly expand its fire and temperature as soon as a fire occurs,threatening the safety of the entire pipeline and personnel.Therefore,investigating the deformation and mechanical behavior of the tunnel structure under high temperature at the present stage is of practical significance.It provides important information for similar structures to prevent and understand fire disasters.In this paper,based on the immersed tube tunnel of Hong Kong Zhuhai Macao Bridge,the general finite element analysis software Abaqus is used to analyze and study the joints which are the most important and the weakest part of immersed tube tunnel,and the following research results are obtained:?1?Based on the fire test of pipe joints and segment joints^[1],it is concluded that the fire protection measures fail at about 1 h,and this is used as a condition for subsequent research to analyze the influence of different fire protection on the temperature field.?2?In order to illustrate the accuracy of the article's simulation application methods,first of all,the above-mentioned test process is analyzed and compared in an all-round way,and it can be proved that the simulation software,shape parameters,and performance indicators used in this paper are in line with the actual situation.?3?Through the simulation of fire temperature field under different working conditions,it can be concluded that the temperature can be transmitted farther under the condition of RABT curve,and the fireproof performance of fireproof board is better than that of fireproof paint.It is suggested that two kinds of materials should be reasonably selected in the later design or research work.?4?The static and thermal coupling simulation analysis of the immersed tunnel shows that the joint structure will not generate excessive stress and deformation under static loading.However,in the thermo-mechanical coupling state,the stress and strain produced by the segmental joints are greater,and they are more likely to be damaged than the pipe joints,and the steel bar at the bottom of the shearing force has basically lost the bearing capacity.