Lookup NU author(s): Lowell Cabangon,
Dr Gaetano Elia,
Dr Mohamed Rouainia
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Current research extensively uses two-dimensional (2D) modelling to simulate tunnels under seismic loading and predict their dynamic response. However, 2D approaches require simplifications in order to capture three-dimensional (3D) effects, such as longitudinal bending and construction sequence, which may underestimate tunnel lining forces. Furthermore, seismic wave propagation has an arbitrary direction with respect to the axis of the structure that causes multi-directional loading for the soil deposit and the tunnel lining. With the availability of high-performance computing, 3D modelling is considered nowadays to be a better approach in predicting the spatial behaviour of tunnels during seismic actions.In this paper, a 3D finite element (FE) model is employed to simulate the behaviour of a shallow tunnel in a typical clay deposit subjected to multi-directional earthquake loading. The clay is described by means of a constitutive model based on typical implementations of Cam Clay. The 3D model is firstly validated against a simplified 2D numerical model. The results of the 3D FE simulations applying the two horizontal components of the input motion independently are then compared with those obtained by simultaneously imposing both components at bedrock level. The comparison in terms of lining forces induced by the earthquake shows a similar response in the transverse direction. However, the longitudinal forces in the tunnel are increased when multi-directional seismic loading is accounted for in the simulations which cannot be captured in a 2D model, thus demonstrating the benefit of using a 3D approach for this class of geotechnical problems.
Author(s): Cabangon L, Elia G, Rouainia M
Publication type: Conference Proceedings (inc. Abstract)
Publication status: Published
Conference Name: 16th European Conference on Earthquake Engineering (16ECEE)
Year of Conference: 2018
Acceptance date: 18/06/2018