| With the development of transportation infrastructure construction in our country,more and more mountainous highway reconstruction and expansion project opening construction appear,In the vicinity of the original tunnel construction of the new tunnel is one of the important content of the reform and expansion project.Blasting seismic waves generated by the blasting method in the new tunnel will endanger the stability and operation safety of the existing tunnel,It will also affect the construction progress and safety of the new tunnel.This paper provides significant theoreticalce and practical value.The dynamic response characteristics of the existing tunnel under blasting load and the change law of the characteristic particle velocity were studied by means of heoretical analysis,the numerical simulation,field test data and tunnel health check,relying on Xin ling tunnel construction project.(1)The research status of small interval tunnel construction at home and abroad is analyzed,Meanwhile,the mechanism of rock blasting and the loading mode of blasting load in numerical simulation are studied.(2)Based on the newly built tunnel excavation blasting vibration caused by adjacent tunnel data as the basis,Blasting vibration velocity Control value of the lining of the existing tunnel was determined according to blasting vibration monitoring data of Xin ling tunnel and adjacent tunnel dynamic response.(3)Three dimensional numerical models of the typical hole are established utilizing the finite element software MIDAS/GTS NX.Influence of newly bulit tunnel on existing one is analyzed by means of accurate simulation analysis according to the dynamic response of the feature points on typical section.(4)Based on the tunnel surface crack extension and other technical indicators of analysis,the paper makes a health diagnosis to existing tunnel and gives safety assurance operation measures. |
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