Study On Collapse Reason Of Shield Tunnel And Engineering Measures Of N-J Engineering

The world come into the stage of rapid development since the industrial revolution,high and new technology change with each passing day,which shows a vigorous development trend.Civil construction is also step into new level with the development of national economic construction.Especially in recent years,with the needs of One Belt and One Road and the 14 th Five-Year Plan,bridges,tunnels,highways and other projects have emerged,domestic companies goes abroad to undertake international projects.With a variety of environmental changes,it broughts a lot of challenges that have not been encountered in domestic,which both appears in technical and management level.Despite the latest technology and the latest means,most of the engineering accidents can only be prevented in advance but still can not be avoided.Therefore,it is very important to study the causes of tunnel collapse and corresponding process measures.This paper focuses on the excavation principle of shield tunneling,combined with the main advanced geological prediction technology,and takes Pakistan N-J project as an example to simplify the shield method,with the real-time exploration and monitoring technical data,use the finite element software Midas GTS NX to analysis the whole process of numerical simulation of shield tunnel and the shield tunnel under complex conditions is systematically analyzed.By comparing the stress and strain of the surrounding rock in the landslide area and the non-collapse area,the main reason for the landslide is that the surrounding rock is changed from Q5 to Q4 and the strength of the rock mass is reduced.The inherent performance of the shield tunnel support structure has a certain degree of lag,failed to support the formation of the surrounding rock in time,tunnel excavation,without restrictions,the surrounding rock deformation increased dramatically.Finally,based on the simulation results,suggestions are put forward for handling the landslide accident.In addition,the simulation results of this paper can also serve as a reference for similar projects to some extent.