Study On Stabilization Of Excavating The Steep-dipping Rock Mass Tunnel

With the rapid development of social economy in our country，highway traffic growth faster and faster.Especially in some developed coastal provinces and regions,traffic congestion situation is very serious.Not only travel a lot of inconvenience to People’s Daily, the traffic congestion at the same time also brought huge economic losses and all kinds of environmental problems., roads is becomingmore and more wide,which is in order to satisfy people’s travel demand, adapt to the increasing traffic.In line with saving resources, reduce costs, protect the environment’s perspective,Large-span flat tunnel is currently a large number of construction.Large-span flat tunnel construction methods and supporting technology research also is not very standard,Various construction methods are used in engineering practice, but there is no unified standard of construction for reference,So forlarge-span flat tunnel excavation methods and supporting technology in-depth research is particularly important..This article based on guangzhou to lechang highway engineering project, to separate large-span flat tunnel as a research starting point, research the standardization of large-span flat tunnel construction and supporttechnology.The research content of this paper is mainly divided into the following severalaspects:â‘ Collect and analyze existing engineering practice and engineering experience,byanalyzing the circular tunnel under different lateral pressure coefficients, oval themechanical characteristics of the tunnel,excavation size influence on surrounding rockstability analysis, through the method of literature research, theoretical research,etc.Summarizes the mechanics characteristics of long-span flat road tunnel, themechanical characteristics of different excavation methods, puts forward the technologyroadmap of this paper.â‘¡Based on three lanes highway tunnel guangzhou to lechang group project,usingthe finite element software MIDAS GTS-numerical simulation analysis,by the size ofthe original design scheme and supporting parameter,In tunnel buried depth of10m,20m and40m as assumptions,in surrounding rock classification on the basis of IV₁, IV₂,IV₃, V₁and V₂grade of surrounding rock as research object,double wall, three stepswere used respectively to four excavation method, CRD, CD construction, finally concluded formation adaptability of four different excavation method.â‘¢With double wall, three steps four excavation method, CRD, CD,using differentside gate size, shoulder height and radius of curvature different condition wereanalyzed.With numerical simulation has been done,By analyzing and comparing themodel of primary support, surrounding rock stress and displacement of surroundingrock stress and the plastic zone size indicators, finally concluded that the fourconstruction methods of standardization construction process.â‘£Combined with the technical specifications and all kinds of information,Throughfield investigation of the completed project,given double sidewall, three steps fourmethod, CRD, CD, primary support reasonable gate length, step length, close distance,length of temporary support to dismantle, secondary lining construction parameters,such as lag distance.