Model tests on seismic performance of double-box underground utility tunnel

A shaking table model test on a double-box underground utility tunnel is conducted based on the theory of similarity simulation test to investigate its seismic behavior. In this test, the Taft earthquake spectra, which are adjusted to have the peak accelerations of 0.2g, 0.4g, 0.8g and 1.2g, respectively to consider the effect of various peak ground accelerations (PGAs), are chosen as the input seismic ones. It is concluded that the maximum dynamic earth pressure has a distribution of reverse "W", and the earth pressure field changes at the end of earthquake. On the whole, the maximum acceleration response, with the amplification from 0.5 to 1.5, increases with an increasing input PGA and decreases with depth. According to the time histories of acceleration and the Fourier spectra, the structures and the surrounding soils basically have consistent acceleration response at the same depth, and the amplitude of the soils is greater than that of the structures under the frequency from 15 to 30 Hz. During the earthquake, there is a larger response of bending moment at corners of the structures, which increases with the input PGAs. At the same time, numerical simulations are carried out with ABAQUS to compare with the results obtained from shaking table tests, which suggests that the results obtained from shaking table tests are highly reliable.