Abstract: To avoid overlarge difference settlement of the buried section, pipe E1, and pipe E2 at connection between island and tunnel of ShenzhenZhongshan link, and overlarge excessive shear of the shear key and the excessive internal force of the pipe joint, prereinforcement measures for the immersed tube foundation of the connection between island and tunnel are conducted, the foundation parameters of different sections are studied, and the rational prelift value of pipe E1 is analyzed and calculated. The key parameters are obtained through laboratory and field tests and largescale threedimensional finite element analysis is carried out to study the stress and settlement characteristics of the pipe. According to the laboratory test, the deformation modulus of 1.0 m thick crushed stone cushion with 30 kPa preloading is determined to be 25.4 MPa in 0~30 kPa section and 8.9 MPa in 30~110 kPa section, respectively. According to the field test, the deformation modulus of the block rock cushion is 50 MPa. Based on the above parameters, the finite element analysis is conducted, and finally the reinforcement measures for the immersed pipe foundation are determined and the prelift value of the pipe is determined to be 70 mm.

Key words: connection between island and tunnel, immersed tunnel, foundation reinforcement, settlement, prelift