Blind prediction of the seismic response of tunnels observed in centrifuge experiments

Elia, G; Rouainia, M; Shahraki, SN

doi:10.1201/b14769-150

Blind prediction of the seismic response of tunnels observed in centrifuge experiments

Lookup NU author(s): Dr Gaetano Elia, Dr Mohamed Rouainia

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Abstract

The response of tunnels and underground structures under seismic actions can be predicted by advanced dynamic methods which can properly take into account the dynamic nature of the loads and the cyclic behaviour of soils. The calibration of such methods should require validation against experimental data, which are seldom available at real scale. Centrifuge modelling is therefore an alternative powerful tool to produce artificial case histories. To this end, dynamic centrifuge tests were carried out in 2007 on circular tunnel models embedded in sand and the experimental data were made available to the scientific community within a blind prediction contest. In this paper the seismic behaviour of a deep tunnel in dense sand is predicted through finite element dynamic simulations using the code SWANDYNE II, which implements the advanced PZ-III model. The constitutive model is calibrated against available laboratory triaxial and resonant column tests. The numerical results are compared with the centrifuge data in terms of acceleration time histories at different locations, induced shear strain profiles and tunnel lining bending moments. This first set of blind predictions shows a stiffer behaviour of the soil deposit with respect to the experimental results, indicating that further investigations of both numerical and experimental results are needed.