Shaking table tests on immersed tunnel-joint-soil

To obtain the dynamic response of the immersed tunnel and its joints under seismic action, with Zhoutouzui immersed tunnel project in China as the background, a series of shaking table tests on immersed tunnel-joint-soil with a scaling factor of 1/60 are conducted under uniform earthquake excitation by using the multiple shaking table test system in Beijing University of Technology. They are performed using a rigid prefabricated continuous model box with the dimensions of 7.7 meters long, 3.2 meters wide and 1.2 meters high. The test system is subjected to strong ground motions from El Centro record, Taft record, Tianjin record and Guangzhou artificial record through horizontal longitudinal and horizontal transverse uniform seismic excitations. The model tunnel joint components are designed to simulate the immersed tunnel joint, and the axial force and deformation of joints are obtained by using the pull-press sensors and laser displacement sensors. The test results show that the acceleration time histories and their Fourier spectra of different model tunnel segments are different from each other. And the seismic response of the tunnel structure is not vibration along with its own features, but is subject to the seismic response of the surrounding soils. Under the seismic excitation with different intensities, the force distribution of joints can provide valuable reference for aseismic design of the immersed tunnels. Under different seismic inputs with different intensities, the displacement of joint 1 is the maximum, and that of joint 2 is the minimum. Such change law makes the whole tunnel along the longitudinal deformation more harmonious. The change trend of displacements along the positive and negative directions at each joint is basicly parallel. The practical water stop of tunnels is in a safe range and will not leak by converting the test results to the prototype data.