Effects of underground explosions on soil and structures based on PD–SPH modeling

In recent decades, researchers have struggled to develop computational models capable of simultaneously simulating the effects of underground explosions on both soil and structures. Traditional mesh-based methods, such as the finite element method (FEM), fail to achieve this due to challenges related to large deformations and discontinuities in soil and structures. To address this limitation, we develop a coupled peridynamics–smoothed particle hydrodynamics (PD–SPH) model, both based on meshfree particle methods. By introducing a robust data exchange algorithm between PD and SPH domains, incorporating a dynamic contact model for different materials in PD domains, and integrating a modified Drucker–Prager plasticity model for soil along with a rate-dependent damage model for concrete, the PD–SPH model effectively captures explosive gas–soil interactions, soil–structure interactions, large soil deformations, and rate-dependent damage and fracture processes in concrete structures.

The effects of underground explosions on soil are then first modeled, demonstrating that the model successfully captures the severe soil ejections and excavation crater formations caused by shallow-buried explosions, as well as subsidence crater formations due to deep-buried explosions. Comprehensive qualitative and quantitative comparisons between PD–SPH simulations and centrifuge tests are provided, with errors below 15 %. In the meantime, the PD–SPH model can also accurately reproduce the damage effects of blast waves in soil on nearby concrete slabs and silo structures. The damage and fracture processes of these structures are analyzed and validated against experimental results. Furthermore, this study also explores the influence of nearby structures on soil ejection and cratering processes. The successful applications of the model to various explosion scenarios demonstrate that the developed PD–SPH model is capable of consistently and accurately capturing the effects of underground explosions on both soil and structures.