Study On The Remedial Techniques And Safety Assessment In Shanghai-Kunming High Speed Railway

In recent years, the railway tunnel construction is booming in China. Regardless of the number, size and speed of construction, China has become a big country with the largest number of tunnel projects, the most complex technical conditions and the fastest development of the tunnel. However, there are more or less problems which have occurred in the operating tunnels or in the even yet not operating tunnel. And some of the tunnel quality defects even have been seriously endangering the traffic safety. Therefore, it is very important to study the technology of tunnel quality defects and safety assessment. By using the theoretical analysis, numerical simulation, aerodynamics verification and other means to make the comprehensive analysis, the mechanism of the quality defects in high speed rail tunnels, the remedial measures and the safety assessment of the tunnel after the renovation are studied in this paper. The main work and the research results are as follows:(1)Based on the tunnel named Bajiaowan in Shanghai-Kunming high speed railway, the quality defects of the tunnel are analyzed in detail by means of comprehensive analysis, and the mechanism of the damage caused by the defects of the tunnel is revealed.(2) By studying the mechanism and influence factors of the quality defects (such as lining cavity, lining cracking and apparent defects etc.) in Shanghai-Kunming high speed railway, nine kinds of reinforcement and improvement measures to control the defects are proposed in this paper. The comprehensive and systematic study on the defects of the remediation plan is made to provide reference for the similar projects.(3) Based on the tunnel named Bajiaowan in Shanghai-Kunming high speed railway, by using the numerical simulation software and the load-structure model, the backfill structure safety behind the tunnel was examined. The safety coefficients of different surrounding rock grades and different influence range of the tunnel are calculated to just meet the requirements of the railway tunnel design specification.(4) When carrying out the tunnel renovation project, the tunnel clearance area will be occupied to lead to the tunnel clearance area decrease and increase the transient pressure of the tunnel and the train, affecting the comfortable sensation of the passenger eardrum. Considering the two kinds of calculation conditions of the tunnel renovation project, the transient pressure inside and outside the train is calculated. The results are not more than the standard of comfort level, which indicates that the technology is reasonable and effective.