Study On Optimization Design Of The Secondary Lining Of Bias Tunnel

Most areas of our country are mountainous and hilly.With the development of basic transportation facilities,the tunnel project has been widely applied in crossing the mountain.At home and abroad the study of tunnel ’ s design and construction is becoming more and more,and for complex geological conditions of the tunnel,such as bias tunnel,its research is still relatively less.For the tunnel bias,the asymmetric load acting on the lining structure is mainly used as the criterion,its formation reasons include the terrain,geological structure and construction factors.At present,the design of bias tunnel often use the method of engineering analogy,but the method can not be completely applicable to similar tunnels,because of each tunnel engineering whose geological condition is relatively complex,design and construction will inevitably result in the waste of manpower and material resources.In this paper,the shallow buried biased section of the entrance of Heda highway Huitougou tunnel is taken as the object of study.Through the field buried earth pressure box to obtain the pressure of the surrounding rock and two contact pressure monitoring data to analyze the ratio of the secondary lining to the surrounding rock pressure.The effects of different cross-slope angles on the internal forces and deformation of the secondary lining structures were discussed in the same way.According to the requirements of the specification to determine its safety.On this basis,optimizing the secondary lining thickness,discussing the relationship between the thickness of different lining and the internal force and displacement of secondary lining structure,analyzing the optimal thickness of the secondary lining from the simulation results.