NUMERICAL SIMULATION OF SURFACE SUBSIDENCE CAUSED BY FREEZING METHOD CONSTRUCTION IN TUNNEL

According to the local horizontal freeing construction ofa metro tunnel, the surface subsidence in the procedure of tunnel excavationis forecasted and the fields of stress and strain in tunnel frozen soil wallis analyzed, the results and the survey of project are equally. Based onthis model, The correlative factors of surface distortion induced by localhorizontal freezing method construction are analyzed. Finally, the resultscan indicate: increasing the thickness of frozen soil wall has a littleinfluence on surface subsidence, but through the method of expanding thearea of frozen soil wall or decreasing tunnel's radius and depth can controlsurface subsidence effectively. The results can provides reference tosimilar construction methods.