Research On Thestability Of Mountain Areas Highway Roadbed Impactedby The Construction Of Undercrossing Tunnel

With the projectof "four horizontals and four verticals"high-speed rail constructionin our country, the construction of railway tunnel is also increasing, more andmoretechnical problems are coming. Because of thehigh-difficulty technology, miscellaneousuncertain factors and serious consequences of the undercrossing tunnel, arousingconcern of experts and scholars at home and abroad.This paper combines Beiyinpo tunnel in Pan County, Liupanshui City,GuizhouProvince, and takes it as the project background. Through the theoretical analysis,fieldmeasurement, finite element numerical simulation method and risk analysis, this paperstudies and explores the stability of mountainareashighway roadbed impacted by theconstruction of undercrossing tunnel.The main research work and achievement is asfollows:①Through the analysis ofthe results of monitoring measurement of undercrossingtunnel,the regulation of actual surface subsidence caused by undercrossing tunnel isobtained.②The finite element calculation modelsofundercrossing tunnel inthree differentlocation are established with the aid of software MIDAS GTS, the results show thatwith the tunnel moving to the slope foot,the settlement of highway roadbeddecreases,and the stability of slope is reduced.③Through the analysis of the finite element calculation models of differentexcavation scheme,the results show that the stability of mountain areas highwayincreases with the decrease of the excavation length,and the side heading method getsthe best effect,bench cut is well enough,full section method causes the worst influenceon stability.④Through the analysis of27examples of the construction of undercrossing tunnel,this paper researchesthe control standardof the stability of mountain areashighwayroadbed impacted by the construction of undercrossing tunnel. The results of the riskanalysis modelestablishedby software Neticashow thatexcavation method is bound upwith the risk of tunnel construction.⑤Reseach the influence mechanismof the stability of mountain areashighwayroadbed impacted by the construction of undercrossing tunnel,the suggestionsof thecontrol measures of the excavation construction of Beiyinpo tunnel are obtained.