Liquefaction‐Induced Damage Analysis of Daikai Station Based on the Porodynamic Coupled Peridynamics Approach

ABSTRACT This study revisits the damage and collapse of Daikai station during the 1995 Kobe earthquake using a coupled porodynamic peridynamic approach. By integrating the strengths of non‐ordinary state‐based peridynamics (PD) for modeling structural localized discontinuities and the finite element method (FEM) for field‐scale soil layers and fluid flow, this approach provides an integrated framework for simulating both the damage and collapse of the station and the liquefaction of surrounding soils. An elastic‐brittle model is used for the station, while the liquefiable sand is modeled with a plasticity model named CycLiq. A staggered solution scheme is proposed to enhance computational efficiency. The model is validated through the simulation of three numerical examples: a one‐dimensional (1D) dynamic consolidation problem, a centrifuge shaking table test involving liquefaction, and the Kalthoff–Winkler test for dynamic fracture. The application of the coupled porodynamic peridynamic approach in simulating the seismic response of Daikai station reveals that liquefaction played a critical role in triggering horizontal displacements and structural failure. The drift ratio of the center column increased significantly after 3 s of seismic shaking, leading to complete collapse when it exceeded 1.0%. Initial cracks appeared in the side walls and ceiling slab, while severe damage to the center column caused the overall collapse. Two significant diagonal cracks in the center column, located at approximately 1/6 and 5/6 of its height, indicate structural collapse. Roof cracks were primarily tensile, while side wall cracks exhibited mixed tensile‐shear behavior. The center column failed in a compression‐shear mode under large bending moments and pressure from the overlying soil.