Shallow Subway Tunnel Lining By Force Characteristic Secondary Research

With the large-scale construction of subway,the subway tunnel drew a rapid growth.The current mining method is adopted in our country the construction of the subway tunnel,the supporting form is given priority to with composite lining,composite lining is consists of two layers of primary support and secondary lining lining structure.At present,there are many researches on secondary lining structure of subway tunnel at home and abroad,but there are few studies on the mechanical characteristics of secondary lining structure in specific granite geology.Based on this,this paper takes Qingdao Subway Line 2 Based on the monitoring and measurement,numerical analysis method is used to study the mechanical behavior of secondary lining of subway tunnel under granite geology.This article through the field measurement and numerical simulation analysis method,the granite of metro tunnel secondary lining structure stress characteristics are analyzed.The main research contents are as follows:(1)Of granite subway tunnel secondary lining structure load share ratio and the secondary lining reinforcement to research the mechanical analysis;(2)Through the finite element numerical simulation method,combining with field measured data,on the basis of the testing load and standardize the load in secondary lining structure under the action of mechanical simulation analysis;(3)The influence factors of secondary lining structure in subway tunnel design are analyzed.Through the research of this paper,the following conclusions are drawn:(1)Through field experiments proposed levels V and VI of surrounding rock of tunnel secondary lining structure ratio were 36.3% and 41.4% respectively.V level of surrounding rock of load sharing ratio consistent with values are given in the specification,and V grade rock load share ratio and the numerical has certain deviation given in the specification;(2)Based on the measured load and standardize the load under the action of the secondary lining structure stress analysis it is concluded that the stress of the difference,and in both cases a detailed analysis of thebearing and the safety of secondary lining,the actual load is obtained under the action of the safety of secondary lining is guaranteed,at the same time also shows that in the specification of secondary lining load calculation method and there are many differences between actual situation;(3)And surrounding rock elastic resistance coefficient of lateral pressure coefficient between the two main factors affecting secondary lining structure were analyzed,and the safety of secondary lining structure is obtained with the lateral pressure coefficient of lateral pressure coefficient is less than or equal to 1(conditions)and the law of the elastic resistance coefficient increases.