Numeircal Analysis For Construction Order And Methods And Bias Terrain Conditions Of Shidaoyangcha Tunnel

With the rapid development of China’s highway traffic construction and moremountain highways,there are many shallow bias tunnels as well as bias voltage ofimport and export of tunnels. Generally speaking the depth of bias tunnel is shallow,or there exists free face, and the surrouding rock is seriously weathered, as a result thesurrouding rock stress of both-side of tunnel is very different. So a slightest mistakein construction may lead to collapse, causing casualties and severe economic losses,which puts forward higher requirements for the design and construction and demandsus should make the construction order and method for bias tunnel be rational andsecure. Therefore, for the researchers and engineers the study and design of the biastunnel has drawn their more and more attention.The paper is based on the Stability of surrounding rock and supporting structureof highway bias tunnel of science and technology project of Highway ConstructionBureau of Jilin Province, and do a research for the shallow bias section ofShiDaoyangcha tunnel in design section of HuiTougou of HeGang-DaLian Highway.The article uses finite element method to simulate to study the stress and the strain ofthe surrounding rock and supporting structure with the variation of constructionmethods and construction sequence of the bias tunnel, mainly completed thefollowing research:(1) The paper establishs the corresponding numerical simulation modelaccording to the engineering geological conditions, geometry and thephysical-mechanical properties of the surrounding rock of ShiDaoyangcha tunnel.(2) Use numerical methods to simulate and analyse the different excavatingsequence of shallow tunnel under unsymmetrical loads. By comparing the plasticzone of surrounding rock, surrounding rock pressure, ground surface settlement,convergence of tunnel inner perimeter and supporting structural stress because ofdifferent excavating sequence, we give the conclution that the the side of shallowerdepth should be excavated firstly. (3) Study and compare the effects of several typical methods of tunnelconstruction of the surrounding rock stress and strain of shallow tunnel underunsymmetrical loads. Through comparing the effects of several typical methods oftunnel construction,that is CD method、 bench cut method、revering core soil withannular exeavation method、single side heading method、double-side-drift method，the paper drew a conclusion that CD method and double-side-drift method are moresuitable for the construction of the bias tunnel.(4) Researche the influence mechanism of how different soil buried thicknessand surface inclination affect rock stress and its strain of tunnel section.