| in the heating pipeline projects, the fixed trestle is an important part to ensure the safe operation of the pipeline. The functions of fixed brackets are restricting thermal expansion displacements of heating pipeline, protecting elbow and tee-fitting and ensure them work safely. The mechanism of fixing trestle and mechanical behaviour of tunnel in high thrust are analyzed in this paper. The conclusions are drawn as follows:(1) In the fixing trestle design, the end restraint was considered to be as simply supported and the high thrust carried by one column. This would make the result much higher than it is. In-situ test result of fixing trestle is analyzed in this paper, calculated the stress through finite element method according to the provided thrust value and cross section of fixing trestle, and then compared the results of them.(2) Calculated the displacement and deformation of fixing trestle by finite element method, and then compared it with the design results.(3) Summaried the in-situ test result for tunnel, analyzed the rationality and security of structure, and reserched the transmission mechanism of large thrust.(4) In the Traditional anti-slip design,the surrounding rock was considered to be as relaxation soil, obviously, it is not appropriate for for the heating pipeline project constructed by shallow undercutting method. In lignt of this problem, In this paper, simulated the shallow excavation construction process of heating tunnel and the slip between surrounding rock and tunnel lining in high thrust by MIDAS-GTS. The results show that the high thrust do a little influence to the corner of the the tunnel.
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