Study On Effect Of Voids Behind Lining On Safety Of Tunnel Structures

.Increases with the size of the tunnel construction in our country,there are a certain percentage of the tunnel due to the geology,topography,climate conditions and the design,construction,operation and the influence of such factors as the different levels of disease,the lining behind the existence of the cavity is a common disease.This kind of tunnel disease seriously threatens the safety of tunnel operation and shortens the service life of tunnel,causing a lot of loss of manpower,material resources and financial resources.Therefore,it is very important to study the influence of lining back cavity on the safety of tunnel structure.In this paper,using the model test and numerical simulation analysis,combining engineering background without hollow is behind the tunnel lining,a single hollow and empty combination effects on the safety of tunnel lining structure,on this basis,the numerical simulation using extension analysis under the fixed depth,fixed position behind the lining cavity size change and different hole combination research influence on tunnel structure safety.The main research work is as follows:(1)The construction of tunnel lining structure is very complicated,which can cause cracking of lining structure and directly affect the safety of tunnel structure.In addition,the hollow combination behind the lining is more significant to the safety of the tunnel structure than the single cavity.(2)The hole depth of the tunnel lining has a significant influence on the internal force of the cavity.The bending moment is changed from the positive bending moment to the negative bending moment with the increase of the void,and it is pulled on the outside of the secondary lining structure,leading to the reverse bending point of the second lining in the arch.The axial force of the cavity decreases with the increase of the cavity width.Therefore,the change of the cavity width of the fixed position will influence the axial force and bending moment of the secondary lining structure.(3)Lining behind the different combination of hole,the impact on the lining of tunnel lining structure safety,when there is a hole on both sides of the arch waist for the tunnel structure safety factor than the dome and the arch waist,hance and arch bottom is significantly lower(4)Model test of cavity effect on lining structure safety rule with the numerical simulation results,and concludes that the different size,different hole combination under the action of the damage evolution law of lining structure.(5)In this article,through large tunnel field of radar detection data analysis and numerical simulation analysis,summarized the causes behind the lining has the main reason for the hole,in addition,behind the lining cavity prevention and to have the empty paper summarizes measures.The results of this study can provide reference for the prevention and repair of the cavity of the lining cavity.