SEISMIC INTENSITY MEASURES FOR THE DAMAGE EVALUATION OF CIRCULAR TUNNELS

The seismic intensity measure (IM) is a key parameter affecting the accuracy of seismic risk assessment, which plays an important role in the performance-based earthquake engineering framework. A reasonable IM can make the prediction of structural seismic responses more accurate. To study on seismic IMs which are suitable for the damage evaluation of circular tunnels, a two-dimensional finite element model was established for the nonlinear dynamic time history analyses of circular tunnel-surrounding rock interaction. The near-field ground motions without velocity pulses and far-field ground motions recommended by FEMA-P695 were used as the input in the numerical model. The overall lining damage indices in compression and in tension were used as the engineering damage measures to estimate the damage states of the lining. The applicability of 20 ground motion IMs commonly used in the engineering practice were investigated. The results show that based on the criteria of efficiency, practicality, proficiency and sufficiency, the best seismic IM for the damage evaluation of circular tunnels is the sustained maximum acceleration (SMA), and the second best is the acceleration spectrum intensity (ASI).