Structural components functionalities and failure mechanism of rectangular underground structures during earthquakes

Seismic performance of rectangular underground structures as a hot topic was studied systematically for decades. However, less attention was paid to the functionalities of the structural components. This paper presents a detailed numerical investigation of the seismic responses of rectangular underground structures and aims to explore the functionalities of the structural components. A three-dimensional numerical model for nonlinear dynamic responses simulations of underground structures was built, and the seismic responses of a rectangular underground structure under multiple ground motions were simulated. Dynamic response data, including internal forces, drifts of the columns and walls were obtained and analysed. Results of the proportions of seismic loads undertaken by the structural components explicitly illustrated the functionalities of the structural components before and during earthquakes. Then the failure process of Daikai station during the Great Hanshin earthquake was simulated, and the loading and deformation capacities of the slabs, as well as the intermediate columns and lateral walls, were presented. In terms of the load carrying capacities and functionalities of the structural components, the failure mechanism of the structures was better to understand, and the intermediate columns as the supporting components for the rectangular underground structures were proposed. The conclusions are beneficial to the seismic design of underground structures.