Abstract:

According to the construction conditions of Su’ai shield tunnel in Shantou, several technical difficulties in engineering scheme design are studied and the solutions are put forward. By adopting the concept of “multilevel shunting”, the traffic connection between the tunnel and the four main roads of the north bank is realized. The design scheme of “drainage board + riprap” is selected for the cofferdam design in the deep sea silt stratum. Rational seismic damping measures are chosen to solve the seismic problems of tunnel structure in 8degree highintensity seismic area. The waterproof design of dual gaskets and the gasket crosssection increasing is taken to meet the waterproof requirements of segment joints opening value when earthquake occurs. For complex strata, the suggestions of shield type selection and configuration are put forward. Exploding pretreatment is proposed for the submarine hard rock intruded into the tunnel so as to reduce shield tunneling risk.

Key words: Su’ai Tunnel, cofferdam design, multilevel shunting, 8degree seismic area, waterproof of segment joints, shield type selection, hard rock treatment