The Technology Research Of The Double Primiary Support In The Large Deformation Tunnel

With the continuous development of railway tunnel in China, the tunnel construction often encountered the large deformation disasters, when large deformation occurred in the tunnel construction,there will inevitably be safety hidden trouble、construction schedule delay、cost rising、the reduced construction quality and a series of problems,to avoid the repeated construction caused by the construction of large deformation, studying on the mechanism of easy generating large deformation of the tunnel project,controlling the occurrence and development of large deformation regularity, taking reasonable construction measures, disaster has been managed before it occurred,so that we can minimize the loss.There are different ways in treating tunnel’s large deformation, the different ways of disposal of large deformation with different supporting effect.This article based on the xingyuan tunnel in revamping/expansion of Musui region line engineering,studying the site geological conditions, design scheme, construction method, the condition of large deformation of surrounding rock and so on, it uses the theoretical analysis、 geological analysis、field experiment、model calculation and so on to research the double primary support in large deformation tunnel’s effect.The main content of the research are as follows:(1) The article comprehensive analyses the regularity of the large deformation tunnel,determines the causes of the large deformation, studies different disposal schemes on the large deformation tunnel.(2) Article analyses the basis of mechanics theory in the double primary support, studies the different mechanical transmission ways existing in the construction process of the double primary support, analyses the stress mechanism of the double primary support and the stress distribution characteristics on the cross section, according to the stress mechanism of the surrounding rock loading taking reasonable supporting ways.(3) We use two finite element analysis software MIDAS/GTS, FLAC3D, Combined with the actual, set up the2d and3d analysis model of the double primary support structure in the tunnel, analyse the structure’s stress changing law in the construction process, calculate the safety coefficient from the different parts of the structure, ultimately determine the distribution way of the first and second layer thickness of the double primary support, the reasonable time to the second initial supporting facilities, combined with field monitoring data to determine the reasonable reserve deformation, at the same time analyse the anchoring system effect on structure safety. (4Construction organization does on-site monitoring measurement at the double primary support passages in xingyuan tunnel, and process the monitoring data, analyses the weak positions during the construction of the double primary support, evaluate the application effect of the double primary support in xingyuan tunnel. And then guides the construction According to the scene monitoring data, ensures the safety of tunnel construction, as well as provides a reliable basis parameters in the design of double primary support.