Shaking table test of immersed tunnel considering the geological condition

Abstract

A series of shaking table tests were conducted on a soil site model and tunnel (Zhoutouzui immersed tunnel of Guangzhou in China) model under uniform seismic excitation. Details of experimental setup are presented with particular focuses on: shaking table array of the four in-dependent sub-shaking tables; a continuous rigid body model consisting of prefabricated box; tunnel joints model used for tests; dynamic similitude design between scale model of soil and tunnel structure and prototype model; design and fabrication of the scaled model tunnel and model soil; and seismic input. A series of testing cases of the shaking tables were carried out on the model soil site and tunnel using input motions with different earthquake acceleration records and seismic amplitudes. Dynamic responses measured from the tests include acceleration of soil stratum and model tunnel, as well as the internal force and displacement of immersion joints. The results demonstrate that the designed model box did not impose significant boundary effect. The simplified model design method not only met the main similarity relation of the small scale underground structure for the shaking table test, but also achieved good experimental results. The location of the bearing force and deformation of the joints can guide the design and strengthen the corresponding measurements through the results. The results can provide a theoretical basis to establish an analysis theory and design method, and help us understand the possible damage mechanism of the immersed tunnel underwater.