Abstract:

It is the first time that Ground Penetrating Shield Technology (GPST) has been developed and applied in China. For the sake of the GPST, the shield launching shaft and the shield arriving shaft needed by conventional shield tunneling technology can be cancelled, the connection section between the underground tunnel and the aboveground tunnel can be bored by shield, the influence of the tunnel construction on the environment can be minimized and the construction period can be shortened. Therefore, GPST has great advantages. However, GPST has disadvantages related to structural deformation, joint seepage and axis deviation. In the paper, the control of the deformation of the tunnel structure, the waterproofing of the tunnel and the control of the posture of the shield are studied by means of theoretical calculation, 3D simulation and model test, with the connection section between the underground tunnel and the aboveground tunnel of the airport line of Nanjing Metro as an example. The study results have been applied in the construction of the mentioned works, which proves that the GPST is feasible and effective. The paper can provide theoretical and practical support for the further application of GPST. 

Key words: airport line of Nanjing Metro, shieldbored tunnel, supershallow overburden, Ground Penetrating Shield Technology (GPST)