Abstract: To systematically investigate the interaction between soil and pipeline caused by shield tunneling and to elucidate the complexities of ground displacement and the changing state of pipe-soil interface contact, a scaled physical model test is employed. This model pipeline is designed to monitor pipeline settlement, pipe void formation, and subsoil pressure. Furthermore, shield tunneling process is simulated through tube extraction, followed by sequential tests on deep soil settling, pipeline response, and pipe soil voiding. The experimental results reveal the following: (1) Deep soil settlement caused by shield tunneling conforms to a Gaussian distribution, with the width of the settlement and volume loss exhibiting nonlinear changes with soil depth. (2) The tests confirm that significant volume loss leads to the formation of voids. The maximum deflection of the pipeline and the void height increase with burial depth, while the void width decreases. (3) During tunneling, voids begin to form at the pipeline bottom when the excavation face is approximately 1.5 times the tunnel diameter away. The primary development of voids occurs within one tunnel diameter from the pipeline.

Key words: shield tunnel, pipeline deformation, void, pipe-soil interaction, model test