Jul 2026· The Physics of Fluids· Vol 38· 0 citations· 41 references
Abstract
Earth dam failures are typically triggered by overtopping, involving complex soil–water interactions and progressive structural collapse. Empirical and semi-empirical models provide efficient estimates of breach parameters and outflow hydrographs, but they usually offer limited resolution of the local stress state, rheological transition, and morphology evolution during overtopping-induced erosion. In this study, a graphics processing unit-accelerated two-dimensional, two-phase dam failure numerical model has been developed based on the Drucker–Prager yield criterion and weakly compressible smooth particle hydrodynamics. Combined with the Herschel–Bulkley–Papanastasiou (HBP) rheological model, the two-dimensional framework represents the yield-stress and strain-rate-dependent behavior of yielded soil during overtopping erosion. Stable inflow boundary conditions are established to simulate overtopping-induced erosion, entrainment, and subsequent transport of yielded soil particles by the water flow. Different failure modes of earth dams with different power law indexes are simulated. By comparing with experimental data, it can be observed that the model captures the key physical phenomena of scour thickening and “headcut” on the downstream slope. A transition in the modeled mechanical response of the eroded soil at the soil–water interface is identified, where the material changes from an unyielded state governed by the Drucker–Prager criterion to a yielded flow state described by the HBP model. Furthermore, the study findings indicate that the migration of fine particles and the rheological evolution of yielding soil during the erosion process lead to a reduction in the strength of earthen dams, which in turn accelerates the expansion of breaches.
Groundwater-related weakening and repeated low-strain-rate disturbances can jointly affect the long-term stability of soft surrounding rock. In this study, a PFC3D model was developed by combining a cumulative residual-strain damage variable with a Weibull statistical damage variable. Water effects were represented indirectly through water-content-dependent mesoscopic parameters and contact-strength degradation, thereby linking macroscopic irreversible deformation to progressive mesoscopic bond degradation. The cyclic responses of mudstone specimens with water contents of 0%, 3%, 5%, and 7.04% were simulated under a roadway-like three-directional, five-face boundary condition, consisting of axial loading, lateral pressure, one laterally constrained side, and one free face. The model reproduced the main stress–strain trends and failure characteristics. From the dry to saturated state, the experimental and simulated peak strengths decreased by 68.51% and 67.44%, respectively. Increasing water content also promoted earlier crack initiation, weakened strong force-chain continuity, and shifted failure from localized shear instability to distributed tensile–shear damage. Energy dissipation became increasingly important as water content increased. These findings clarify the mesoscopic damage mechanism of water-bearing mudstone under coupled water-induced softening and low-strain-rate cyclic loading, providing a reference for stability assessment and support design in underground soft-rock engineering.
Sen Yang, Guichen Li, Xiaofang Wo et al.· Applied Sciences· 0 citations
Rock failure under hydromechanical coupling is a complex process that has attracted considerable attention in deep underground engineering. In this study, a hydraulic coupling analysis method for rock loading and failure is developed based on the finite–discrete-element method (FDEM) combined with the grain-based model, which integrates the dual-medium seepage–stress coupling theory to simultaneously capture pore and fracture seepage. Numerical simulations of sandstone under varying confining pressures were performed and validated against laboratory experiments, and the effects of confining pressure and weak joint content on the permeability evolution were systematically investigated. The results demonstrate that the permeability evolution during loading is governed by the competitive interplay between matrix seepage and fracture seepage, exhibiting a nonlinear pattern. Higher confining pressures prolong the stage of slow permeability growth, whereas an increase in the weak joint content reduces strength and stiffness, leading to an earlier occurrence of the permeability inflection point and an enhanced dominance of fracture flow in controlling macroscopic permeability. These findings provide new insights into the mechanisms of hydromechanical coupling in fractured porous rocks and offer theoretical support for predicting and controlling hydraulic hazards in deep rock engineering.
Aifeima Aihetamu, Chong Shi, Zheng Yao et al.· International Journal of Geo...· 0 citations
Aiming at the significant pore structure reconfiguration and mechanical response evolution of offshore unconsolidated sandstone reservoirs during long-term high-intensity waterflooding development, this study proposes a novel fluid–solid coupling mathematical model incorporating waterflooding erosion effects. This method enables coupled simulations of reservoir deformation, fluid flow, and waterflooding-induced pore structure evolution. Compared with conventional methods, the proposed method not only accounts for the influence of mechanical responses on reservoir seepage parameters, but also incorporates pore structure evolution induced by waterflooding erosion under high-intensity waterflooding conditions. The model is validated against MRST, demonstrating its reliability. Multiple case studies are further conducted to systematically investigate the impacts of waterflooding erosion and fluid–solid coupling on the evolution of reservoir properties. The results indicate that under long-term high-intensity waterflooding conditions, waterflooding erosion dominates the evolution of reservoir petrophysical properties in the vicinity of injection wells. Although the fluid–solid coupling effect is weakened under high-porosity conditions, waterflooding erosion remains across different porosity reservoirs. It is a key factor controlling reservoir petrophysical property evolution during long-term high-intensity waterflooding.