Catastrophic failure mechanism of underground complexes under deep construction disturbance

The burgeoning demand for land resources in cities has spurred the development of intricate underground infrastructure networks. Therefore, evaluating the performance and stability of entire existing underground complexes in the event of construction-related disturbances becomes increasingly crucial for ensuring overall urban resilience. This paper adopts a coupled modeling technique of the Finite Element Method (FEM) and Smoothed Particle Hydrodynamics (SPH) for the analysis of catastrophic failure mechanisms in underground complexes, with a focus on disturbances due to nearby tunneling. Two-dimensional centrifuge model experiments were used to thoroughly calibrate the coupled FEM-SPH method, validating its accuracy and suitability for the simulation of soil–structure interaction problems. Subsequently, a full-scale integrated model of the underground complex and formation in a given area was established, including the subway network and highway system. Taking into account the longitudinal connections of the tunnel segments, the catastrophic coupling mechanisms related to construction disturbances in deep tunneling were investigated. The results indicate that collapsed soil caused by deep construction disturbances spreads through the gaps between the tunnels towards the ground, acting as a force-transmitting medium to correlate the deformations of the different structures. The response of the structures was evaluated using five different patterns of deformation, including tunnel settlement, dislocation, opening, rotation, and ovalization. In addition, the evolution of the performance of the underground complex during construction disturbances was analyzed using three types of indicators. Finally, the assessment of the catastrophic failure degree and the identification of vulnerable areas within the complex were carried out.