The safe operation of cascade dam groups is critical to water resource management and disaster prevention. However, existing methods are ill‐suited for real‐time structural health monitoring (SHM) and system‐level health assessment due to their static nature and inability to model dynamic interdependencies. To bridge this gap, this study proposes ordered entropy as a novel, systems‐theoretic metric that quantifies the dynamic health state of an entire dam group. We develop an integrated, monitoring‐data‐to‐health‐assessment framework that systematically transforms raw monitoring data through robust preprocessing (Apriori–DBSCAN), spatial field reconstruction (Co‐Kriging), and multisource information fusion (order degree with PCA). By integrating the maximum entropy principle and extreme value theory with the derived entropy sequence, we establish a novel method for estimating the real‐time failure probability as a health state quantification output that serves SHM of hydraulic systems. Applied to the Y River cascade dam group, the framework yields a service‐state failure probability of 1.33 × 10 −6 –1.47 × 10 −6 per year, demonstrating its rationality and practicality, with the temporal variation of failure probability showing a dominant correlation with reservoir water level—consistent with engineering mechanics principles and operational observations. This work provides both a new theoretical paradigm and a practical toolchain for advancing data‐driven SHM, prognostic health management, and operation state awareness of hydraulic infrastructures.

Landslide dams, as a special type of earth dams, are characterized by complex geomorphological features and geotechnical properties. The failure of landslide dams induced by seepage should not be overlooked. This study introduces a calculation method for analyzing the slope stability of landslide dams with three different material compositions under seepage conditions. Furthermore, the influence of spatial heterogeneity in particle size on the stability of landslide dam slopes subjected to unsaturated seepage is investigated using the random finite element method combined with Monte Carlo simulation. This paper provides a reference for the reliability evaluation of landslide dams with different material types.

Cascade dam groups are crucial for water resource management and hydropower generation, yet their complex interdependencies and potential risks pose significant challenges to risk assessment. Current approaches often overlook inherent resistance characteristics and struggle with the fuzziness and uncertainty in evaluating risks. To address these issues, this study develops a comprehensive risk assessment framework that incorporates inherent resistance features. Hesitant fuzzy theory is applied to quantify key indicators, including failure probability and consequences. A non-equal interval division method is proposed for risk level assessment, and evaluation criteria are established based on established risk prevention guidelines. Furthermore, an evidence theory and cloud model-based approach is introduced to effectively handle the inherent fuzziness and uncertainty in cascade dam group risks. The impact of various factors on dam group risks is quantified through the analysis of risk evaluation indicators. Case studies demonstrate the model's effectiveness, with a highest merged probability value of 0.9985 classifying the cascade dam group's risk as 'general risk', aligning with its observed operational safety. This study provides a robust and practical framework for comprehensive risk assessment and quantitative analysis of influencing factors in cascade dam groups.

Severe upstream dam failures can attenuate at the receiving embankment, whereas weaker inherited floods can be re-amplified by more than twofold. This source-response asymmetry is not captured by flood-routing or peak-superposition interpretations. For compacted embankment dams, cascade outcome is controlled by the receiving embankment, which filters, delays, transmits, or reactivates inherited forcing according to breach duration, release geometry, and resistance state. Large-scale flume experiments on seven two-dam cascade scenarios under progressive overtopping and shock loading reveal two downstream response regimes. In the regulated regime, the classical overtopping-breach sequence remains organized, and hydraulic transmission is partly separable from structural release. In the overwhelmed regime, erosion and release are compressed into a short peak-forming interval through either saturation-induced structural weakening or hydraulically coherent surge transmission. This bifurcation is organized by a hydro-structural coordination framework in which amplification requires the downstream breach to develop in time, and to open widely enough, before the inherited pulse dissipates. Across the seven cases, peak transmission (AQ) ranges from 0.48 to 2.21, whereas source-scaled downstream hazard (λQ) reaches 3.82 even when AQ < 1. Local peak amplification at a susceptible receiving dam and efficient transmission of a high-energy source are therefore distinct risk modes often conflated by peak-ratio analyses. These results shift cascade interpretation from source-driven routing to receiver-controlled hydro-structural conversion, and indicate that cascade-risk assessment requires tracking breach duration, release geometry, and evolving downstream resistance at each downstream node.

The rigorous simulation of hydro-mechanical coupling involving large deformations is a pivotal challenge in analyzing geotechnical disasters. While the Material Point Method (MPM) offers significant advantages in modelling coupled problems, its efficacy is often compromised by the geometric inconsistency between the background grid and evolving physical boundaries, alongside non-physical oscillations during cell-crossing. To address these challenges, this study establishes a robust computational framework for a hydro-mechanically coupled MPM with dynamic boundary conditions. The core innovation lies in a novel strategy for boundary handling and stability control. Specifically, a mass-gradient-based normal vector reconstruction algorithm is introduced to rigorously define the geometric orientation of moving boundaries, ensuring continuity even under extreme topological changes. A unified flow correction-velocity constraint algorithm is further developed to automatically distinguish and seamlessly transition between hydraulic head and flux boundaries. To ensure numerical stability near these dynamic interfaces, a cell-averaged pore water pressure smoothing technique is incorporated to effectively suppress non-physical oscillations. The accuracy of the proposed framework is validated through benchmark problems, including one-dimensional consolidation and unsteady seepage. Finally, the framework is applied to simulate the complete process of seepage-induced dam failure. The results accurately reproduce the mechanisms of effective stress degradation, shear band coalescence, and retrogressive failure. Crucially, the simulation captures transient pore water pressure spikes at the onset of macroscopic instability, providing direct evidence of the shear-volume coupling mechanism induced by soil dilatancy. This study demonstrates that the proposed method effectively resolves the difficulties in dynamic boundary imposition and oscillation control, offering a reliable computational tool for the stability assessment of complex hydromechanical coupling problems.

Non-cohesive earth dams are widely distributed in natural and semi-engineering scenarios, and overtopping-induced breaches are their most catastrophic failure mode. Accurate prediction of the overtopping failure process and breach evolution is critical for risk assessment, emergency management, and dam design optimization. In this study, an improved 3D numerical method is developed to simulate the coupled hydrodynamic-erosion-breach evolution processes of non-cohesive earth dams. The model based on the finite volume method integrates three core modules: a hydrodynamic module based on the Reynolds-Averaged Navier-Stokes equations with the Volume of Fluid method for free surface tracking, a dam material erosion module considering particle entrainment and transport mechanisms of non-cohesive soils, and a breach development module coupling erosion and gravitational collapse. To validate the model, two levels of verification are conducted: first, a classic benchmark dam break case is employed to confirm the feasibility of the hydrodynamic and breach evolution algorithms; second, published flume experimental data of non-cohesive earth dam overtopping failures are adopted to evaluate the model accuracy in predicting breach hydrographs and spatiotemporal evolution of breach geometry. The results demonstrate that the proposed model accurately reproduces the key characteristics of overtopping failure with high fidelity. The predicted breach flow rates and flow depths are in excellent agreement with experimental observations, with relative errors less than 5% for both peak discharge and time to peak. Consequently, this study provides a reliable numerical tool for detailed simulation of non-cohesive earth dam breaches and offers scientific support for emergency management.

Cascade dam groups are critical to water resource management but face complex, interconnected risks due to hydraulic interactions and structural dependencies. Traditional risk assessment methods often overlook the transfer effects of risks within such systems, leading to incomplete safety evaluations. This study develops a comprehensive risk transfer evaluation indicator system that incorporates inherent resistance characteristics and hydraulic risk transfer effects. The relative importance of each indicator is determined by combining ranking relation analysis (G1) and entropy weighting methods. A risk transfer model is then devised, and the risk transfer coefficient is quantified using the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). To identify the most hazardous failure path, the minimum system reliability criterion is introduced, employing structural non-probabilistic reliability analysis theory optimised via the Harris Hawk optimisation (HHO) algorithm. A case study of a three-dam system demonstrates the method's effectiveness, identifying the path from Dam B to Dam A as the most critical. This approach provides technical support for the failure risk assessment of cascade dam groups and offers key insights for prioritising safety interventions.

The simplified physically-based dam breach models are effective tools for predicting outburst flood hydrographs of landslide dams. However, their predictive reliability is severely constrained by parameter uncertainties, particularly regarding in soil erosion. To address this, this study applies an established Bayesian multilevel framework to develop a probabilistic modeling approach for landslide dam breaches. A highly computationally efficient simplified model is developed and subsequently embedded into a Bayesian multilevel framework to systematically quantify the uncertainties in the erosion parameters. Using observational data from ten documented landslide dam failure cases, model inversion is executed via a Markov chain Monte Carlo simulation combining Gibbs and Metropolis-Hastings sampling. As a primary contribution, this study quantifies the uncertainty of the erosion parameter specifically for landslide dams for the first time. Following inversion, parameters with non-informative priors are updated to well-defined posterior distributions with distinct peaks. Furthermore, the results reveal that approximately two-thirds of the uncertainty in the predicted peak discharge stems from the epistemic uncertainty of key parameters, with the remainder attributed to residual error. This framework significantly improves the reliability of outburst flood predictions and substitutes subjective empirical assumptions with data-driven probabilistic inference, providing highly valuable insights for downstream hazard mitigation.

Frequent earthquakes have significantly exacerbated instabilities in slopes. Accurately evaluating slope stability during seismic events remains a challenging task. In this study, a new method is proposed to evaluate the evolution of seismic stability of a slope based on shear deformation energy calculated by means of shear stress versus shear displacement curve. Shaking table tests are mainly adopted to demonstrate how this proposed method can be used and to validate the feasibility of the method. Seismic acceleration of the slope, soil pressure behind the pile, and displacement of the pile are monitored in shaking table tests. The obtained data on seismic acceleration are used to calculate permanent shear displacement using the Newmark analysis method. By integrating the test data, the evolution of seismic slope stability is analyzed using the proposed method. The results show that the proposed method can be used to calculate the decreasing stability safety factor and to analyze the dynamic change of seismic stability throughout the shear process. This approach offers a quantifiable assessment of slope stability during and after seismic events and thereby provides a scientific foundation for disaster prevention and mitigation strategies.

High earth-rock dams and large reservoirs have been widely constructed in mountainous river valleys. These areas contain a significant number of potential landslide areas, which can be triggered by external factors, such as earthquakes, heavy rainfall, or water level fluctuations. The impact of landslide-generated waves can lead to the breaching and failure of earth-rock dams. To investigate the breaching mechanisms of earth-rock dams and the erosion patterns caused by landslide-generated waves, a series of integrated physical experiments was conducted to simulate the process of wave-dam breach scenarios. The wave climbing process in front of a dam and the erosion characteristics of different types of waves were analysed. Critical criteria for wave-induced dam erosion and breaches were also proposed. The breaching process was examined under the influence of various factors. The results indicate that the dam breach can be divided into three stages under the impact of landslide- generated waves: surge run-up overtopping stage, surge impact erosion stage, and conventional overtopping erosion stage. When a wave climbing height in front of the dam is higher than the dam height (Ri* > (hd)i-1), the dam crest is continuously eroded; when the average water level in front of the dam is greater than the height of the dam after erosion (hi > (hd)i), the earth-rock dam breaks. The erosion of the dam body induced by waves was more severe under identical hydraulic conditions than dam breaches under natural overtopping. This results in faster breach development, earlier breach initiation, higher peak discharge, longer breach duration, and greater overall risk.

Landslide-induced waves pose significant risks to human life, property, and infrastructure, especially in relatively narrow channels where wave propagation differs from that in reservoirs or coastal areas. This study introduces a drift-flux model, treating the two-phase mixture as a whole to simulate flow-like landslide-induced waves efficiently. The model combines the renormalization group k‑ε turbulence model and volume of fluid method to accurately describe wave formation and propagation. After verification through mesh size convergence tests and a benchmark experiment, the model is applied to the Baige landslide-induced waves in a narrow river channel on October 10, 2018. The results indicate that wave evolution occurs in four stages: run-up, inundation, run-down, and propagation along the valley. The run-up heights and wave decays vary between upstream and downstream locations at the same distance from the landslide center, depending on the extension direction of the river channel. The numerical predicted maximum run-up height of the Baige landslide-induced waves on the opposite hill slope is 112 m, consistent with the actual situation. However, the maximum run-up heights predicted by empirical equations are lower than both the actual and numerical simulated values due to the lack of consideration of multiple wave reflections in a narrow river channel. Utilizing the previous empirical equations to evaluate landslide-induced waves in a narrow river channel may result in underestimating their hazard. This study contributes to the risk assessment of landslide-induced waves in narrow water bodies, and its findings are essential for safety management and siting decisions regarding infrastructure and facilities.

This study conducts flume model tests on the overtopping failure of asphalt concrete core dams (ACCDs), considering varying asphalt contents of core walls, environmental temperatures, dam heights to explore breach mechanisms for the first time. Test results show that the overtopping-induced breach process is divided into three stages: backward erosion of dam shell materials on the downstream slope until the first fracture of the core wall, multiple fractures of the asphalt concrete core until the occurrence of peak breach flow, and breach stabilization. The decrease of asphalt content or increase of the environmental temperature resulted in higher peak breach flow and earlier time to peak. These test results were employed to develop a predictive formula for the displacement of the core wall before its first fracture. The dam height significantly affects the peak breach flow but has little impact on the time to peak. A simplified numerical model is developed using the Burgers model, the principle of energy conversion, and fracture mechanics. This model accounts for the deformation and displacement of the asphalt concrete core wall after its exposure, the initial crack length, and the crack growth process. The calculated and test results show good agreement with less than ±15% relative error.

Grain composition of debris flow material (including sources, flow bodies, sediments, and deposits) satisfies the unified grain size distribution (GSD), P(D) D–µexp(–D/Dc), thus the GSD function provides a pair of integrated parameters µ and Dc to describe grain mixing during debris flow evolution. It is observed that µ decreases and Dc increases from fluid to deposit, coinciding with the entrainment of fine grains and loss from deposit. This study explores the GSD variations through the analysis of data from field observations and simulation experiments. It is found that debris flow is “well-organized” in that the flow regimes and dynamical parameters are strongly correlated to the GSD. This implies that debris flows originating from various source materials are likely to find their own critical state defined by µ and Dc, i.e., Dc governs collisional regimes (via coarse-grain dominance) and µ controls viscous regimes (via fine-grain modulation). This reveals the underlying universality of diverse appearances of debris flows, and the findings are heuristic in understanding the granular effects in debris flows and formulating more realistic dynamic models.

This paper presents a time-dependent reliability analysis method for concrete-faced rockfill dams (CFRDs) by integrating multiple failure modes and multi-source monitoring data via Bayesian networks. Initially, two sub-Bayesian networks are constructed to fuse dam parameters, two related failure modes, and three types of monitoring data. Subsequently, the prior failure probabilities of the dam system for each period are calculated through the time-variant response relationships among network nodes. These response relationships introduce a time-variant term to quantify the effects of water level and creep. Finally, various types of monitoring data are utilized to update parameter distribution, resulting in the posterior failure probabilities. The proposed method is applied to 233-meter-high Shuibuya CFRD. The results indicate that Bayesian networks offer a more comprehensive and reliable assessment. Water level induces periodic variations in system reliability, while creep drives the long-term trend by increasing slabs' failure probabilities. The failure probabilities of dam system increase over the initial ten years and stabilize as creep converges. The slabs’ failure probabilities vary from location. Seepage failure probability is primarily dominated by the most critical slab. Utilizing multi-source monitoring data can reduce uncertainties, mitigate the interference of localized abnormal data, and identify potential failure locations. This approach supports enhanced dam safety management.

Since its inception, the Shields curve has been a fundamental tool for analyzing sediment entrainment thresholds. Nevertheless, the original formulation contains inherent limitations: both sides of its governing equation incorporate interdependent hydrodynamic parameters (flow velocity and shear stress), rendering explicit determination of the critical incipient shear stress mathematically intractable. To address this circular dependency, researchers have developed revised methodologies involving auxiliary dimensionless parameters and direct computational frameworks. This study synthesizes the prevalent Shields curve variants and their associated dimensionless parameters, and systematically evaluates their predictive accuracy using experimental data from flume tests documented in the literature. Sensitivity analyses of Shields parameters reveal that while different dimensionless parameters exhibit distinct functional forms, they maintain strong mutual correlations. When constrained by identical shear stress solution parameters, formulations combining any pair of dimensionless parameters achieve comparable computational precision. Correlation analyses further demonstrate that parameterization schemes incorporating the particle Reynolds number minimize experimental data scatter. Through regression modeling, a novel expression for critical shear stress of non-cohesive particles is proposed. Comparative validation confirms that the new model outperforms the conventional approaches in both predictive accuracy and experimental agreement.

Soil erosion characteristics in embankment dam materials play a crucial role in the evolution of breach morphology because of overtopping-induced dam failure. This study develops a testing technology that directly measures the shear stress at the water-soil interface by detecting the microstrain in the soil. Consequently, a soil erosion testing device (SETD) is designed to directly measure both the critical shear stress necessary for soil erosion initiation and the erosion rate. The SETD includes a hydrodynamic system, a soil erosion system, and a data acquisition system. The hydrodynamic system continuously observes the flow velocity adjacent to the soil sample. In contrast, a sample lifting component monitors the erosion progress in real time, maintaining a consistent height at the water contact point to ensure uninterrupted erosion. The erosion system utilizes a shear stress measurement component to measure the flow shear stress at the water-soil interface directly, and the data acquisition system automatically logs both the flow shear stress and the erosion rate of the soil sample. The validation experiments demonstrate a linear correlation between the erosion rate of cohesive soils and flow shear stress. The critical shear stress for initiating erosion increases significantly with higher compaction levels and clay content. For noncohesive soils, the experiments have established a distinct linear correlation between critical shear stress and median grain size on a double-logarithmic scale, underscoring the impact of particle size on erosion characteristics. Based on the experimental data presented in this study, a predictive model was developed for the critical shear stress and erosion coefficient of cohesive soils. Results indicated that by optimizing model parameters and incorporating more soil-related characteristics, the model effectively captured the relationship between critical shear stress, erosion coefficient, and soil properties. This provides a scientific basis for selecting erosion parameters of dam materials in dam breach simulations.

The failure risk of tailings dams has significant impacts on downstream environments and safety. This study investigates the effects of tailings slurry concentration and inflow velocity on the failuring process of tailings dams through physical model experiments. Experiments were conducted under low-, medium-, and high-concentration slurry conditions with varying inflow velocities, focusing on the role of slurry fluidity in failure evolution. Discharge-time curves were analyzed to reveal dynamic characteristics of the dam-break process. Results indicate that as slurry concentration increases, fluidity decreases, prolonging the failuring process and reducing discharge rates. Inflow velocity significantly affects the initial failuring rate, with higher velocities accelerating failure expansion. The study demonstrates that slurry concentration and fluidity critically influence erosive capacity during failuring, particularly under low viscosity conditions where failuring becomes more intense. Higher inflow velocities exacerbate failure development, leading to severe dam erosion. Rational control of slurry concentration and flow velocity can effectively mitigate tailings dam failure processes, reducing downstream hazards. This research provides experimental insights for discharge prediction and disaster mitigation strategies during tailings dam failures.

ObjectiveAsphalt concrete core dams (ACCDs) exhibit complex hydraulic–structural responses during overtopping failure due to the viscoplastic nature of asphalt concrete and its sensitivity to temperature and material composition. Compared with conventional earth–rockfill dams, the failure behavior of ACCDs involves a strong coupling between hydraulic erosion and structural deformation, particularly within the core wall. However, systematic experimental evidence regarding breach evolution under varying environmental and structural conditions has remained limited. This study aimed to clarify the overtopping-induced breaching mechanisms of ACCDs and to elucidate the governing effects of the environmental temperature, asphalt content in the core wall, and dam height on breach erosion, core wall deformation, and temporal variations in breach discharge.MethodsLarge-scale flume model tests were conducted using a 40 m long physical modeling system constructed according to Froude similarity. Seven experimental groups were designed to isolate the effects of three major factors: environmental temperature (0°C, 15°C, 30°C), asphalt content in the core wall (5.2%, 6.0%, 6.8%), and dam height (0.6 m, 0.9 m, 1.2 m). All dams employed a vertical asphalt concrete core built from hydraulic asphalt (70# binder) and a graded aggregate mixture formed following a prescribed particle-size distribution. The dam body was compacted layer by layer to achieve a relative density of 0.55.ConclusionsLarge-scale experimental evidence demonstrated that overtopping failure of ACCDs is governed by a coupled hydraulic–structural process. The breaching sequence consistently included initiation, development, and attenuation stages, with the core wall deformation and breach enlargement playing a decisive role in controlling energy accumulation and release.