Surface Control Techniques for Tunnels in Karst Areas Under Crossing Airport Taxiways

Under the conditions of karst development and soft upper and hard lower strata, the ground settlement control of tunnel under airport taxiway construction is stricter than that of ordinary tunnel. Tunnel construction methods and karst disposal measures are also particularly important. It is an engineering problem that needs to be solved urgently to ensure the safe passage of the tunnel under airport taxiways without suspension. Taking the intercity railway tunnel under the taxiways T3 and T4 of Guangzhou Baiyun International Airport as the research object, this study carried out theoretical analysis and field test on Karst Treatment Measures and surface settlement control measures. The Karst Treatment Measures under different condition and the "Pile Supporting Plate" structure system are proposed to support the taxiway. The effect of the system is analyzed by numerical method, and the on-site surface settlement is monitored. The research results shows that the maximum settlement of T3 and T4 taxiway surface monitored on site are 5.90mm and the differential settlement is 0.12‰. The numerical simulation results are similar to this value, and do not exceed the settlement control standard of taxiway. Through the research, the key technologies for the construction technique of tunnels under airport taxiway of airport taxiway under tunnel in karst area and upper soft and lower hard strata are is formed, the karst disposal measures for tunnel construction in karst areas is summarized and the "pile support plate" protection system for ground settlement control when tunnels under pass the airport without suspension is proposed ,which can provide reference for similar projects.