Study On The Method Of Detecting Second Lining Thickness Of Highway Tunnel

With the development of highway construction in our country,more and more highway tunnels have been built.As the tunnel second lining thickness is vital to ensure the quality of tunnel construction and the safety of tunnel operation,tunnel lining thickness detection method research has certain theoretical and practical significance.This paper introduces the current detection methods of highway tunnel second lining,analyzes the advantages and disadvantages of various detection methods,and puts forward the drilling method to solve the problem that the radar detection of the stratification of the tunnel is not obvious.From the premises of the drilling method to how to determine the number,depth and location of holes,this paper thoroughly explains the drilling process and the basic principles;and then according to the actual situation and years of experience in the field,concludes the criteria of drill.And then combined with the reinforcement ratio of the surrounding lining of the tunnel,the paper puts forward the statistical method of the qualified rate of the three lined concrete lining thickness:when the reinforcement ratio is less than 30%of the total length,the radar detection can be used directly;when the reinforcement ratio is greater than 30%of the total length,for the reinforcement segment,use drilling method,and for the non-reinforcement segment,use radar detection,and then according to the qualified rates of the two methods,use the weighted average method to obtain the total pass rate of thickness of the tunnel;when the tunnel’s second lining is all reinforced,directly use drilling method;Finally,relying on the tests of Baotou-Maoming High-speed Guangdong section T2 Baishigang tunnel and thickness detection of tunnel’s second lining,the results verify the feasibility and effectiveness of the combination of drilling method and radar method.This method has been supervision inspection association of guangdong province into the tunnel second lining NDT work instructions.This paper may provide reference for the detection of the thickness of second lining of similar highway tunnels.