Transverse response of utility tunnel under near fault ground motions: Multi-shake table array tests

This paper presents shaking tests conducted on a 1/30-scale utility tunnel model employing a multi-shaking table array system. The model utility tunnel-soil system was subjected to input motions simulating near-fault ground motions with and without velocity pulse. The test data were collected and analyzed including acceleration, strain and displacement of the soil bed and model tunnel responses. The soil data analysis indicated that the boundary effect of the model soil box used in the test was negligible. The observed small soil settlements confirmed that the physical and mechanical properties of the model soil did not change significantly in tests. The results also demonstrated that, in general, the transverse dynamic responses of the utility tunnel and surrounding soil under near-fault ground motion with velocity pulse were much greater than the case without velocity pulse. Therefore, the effect of velocity pulse should be considered in the design of utility tunnels.