This session highlights advances that combine physical experiments and numerical simulations to improve landslide hazard assessment. We welcome contributions addressing initiation, propagation, deposition, and impact processes; data–model integration; and scaling from laboratory to field. The emphasis is on approaches that link fundamental process understanding with practical applications, including early warning systems, scenario analysis, and risk-informed design, across diverse landslide types, materials, and environmental settings.
We invite presentations on landslide hazards that employ advanced physical experiments (laboratory or field) and numerical simulations (e.g., DEM, SPH, MPM, CFD). Relevant topics include, but are not limited to: innovative experimental methods at multiple scales; hybrid and multiphase modelling approaches; triggering mechanisms; material and rheological characterization; runout and entrainment modelling; model calibration and validation; multi-hazard interactions; and applied case studies.
Understanding the rheological characteristics of rapid granular flows is essential for elucidating numerous geological phenomena, including abrupt fault sliding and high-velocity landslide movements. This study employed rotary shear tests on diverse granular specimens, covering a broad shear velocity spectrum from low to high magnitudes and under varied normal stress conditions, to explore the variation of mechanical properties across different flow regimes. Experimental outcomes indicated that under shear velocities below 1 m/s, the steady-state shear resistance exhibited dependencies on both normal stress and material constituents, accompanied by a consistent velocity-related pattern. Specifically, the steady-state shear resistance of the tested samples underwent a transformation: transitioning from velocity-strengthening behavior at low shear velocities (≤ 0.1 m/s) to velocity-weakening behavior when shear velocities exceeded 0.1 m/s. Notably, when shear velocities surpassed 1 m/s, the steady-state shear resistance became insensitive to normal stress and material composition, converging to a comparable steady-state value for both crushable and non-crushable granular materials. While normal stress and mineral composition exerted minimal impact on steady-state shear resistance under high shear rates, they significantly modulated the weakening rate—defined as the transition process from peak strength to steady-state shear resistance. This weakening rate was found to be closely associated with the material's crushability, quantified by the Weibull modulus. These findings offer valuable insights into the underlying mechanisms controlling the hypermobility of large-scale landslides and the rapid dynamic processes of geological granular flows.
How to cite: hu, W.: Effects of Normal Stress, Shear Rate and Granular Material Types on Steady-State Shear Resistance and Viscosity in Rapid Dry Granular Flows, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17299, https://doi.org/10.5194/egusphere-egu26-17299, 2026.
Gravitational mass movements, such as debris flows, rock and snow avalanches, move downslope through complex terrain, where bends, undulations, and channel constrictions strongly influence flow behavior and deposition patterns. Accurate understanding and modeling of these processes are critical for effective hazard assessment and risk management. However, most experimental flume setups idealize the terrain as planar. Therefore, the verification and validation of numerical models is often performed in simplified terrain conditions, where curvature effects, flow detachment from the terrain, and slope-normal accelerations do not emerge and, thus, do not challenge the assumptions and simplifications of various numerical models.
In this work, we performed flume experiments on complex topographies to generate a novel dataset of flow kinematics and depositional patterns under varied initial and boundary conditions. We used dry granular flows (quartz sand, 0.7 − 1.2 mm), released into a half circular channel with diameter 0.2 m. Along the 4 m inclined slope, complex topographical features are introduced through a modular 3D printed configuration. Slope (25°, 35°), release mass (2 − 20 kg), bed roughness (smooth and rough, 0.7 − 1.2 mm), and terrain features such as bends and bumps are tested. Flow fronts are tracked with video cameras, flow depths are measured with laser sensors, and deposition is quantified via pre- and post- experiment laser scans. We compare the runout length and mobility angle throughout the different experiments. As expected, basal roughness reduces flow velocity and runout
distance, and alters deposition patterns. Increasing the flow mass promotes the formation of roll waves and longer runout. Bends lead to energy dissipation, thereby promoting upstream deposition. Longitudinal terrain bumps induce the detachment of material from the channel bed at the higher slope angle or the deposition upstream of the bump at the lower slope angle.
These experiments provide a unique dataset of granular flows with systematically varied terrain features and well defined boundary conditions. They are designed for direct comparison with numerical models, providing a realistic benchmark to assess model performance and to identify limitations of different approaches for simulating granular flows over real topographies.
How to cite: Frieß, P., Vicari, H., Gurol, L., Di Pietro, T., Hehli, G.-A., and Gaume, J.: Granular Flow Behavior over Complex Topography: Insights from Flume Experiments, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6414, https://doi.org/10.5194/egusphere-egu26-6414, 2026.
Field observations have shown that forests can serve as natural barriers to reduce landslide runout distance by dissipating energy during impact and enhancing resistance through tree entrainment. While recent physical modelling studies indicated how forest spatial configurations enhance energy dissipation, they oversimplified trees as rigid, unbreakable elements, neglecting the critical role of tree failure in landslide dynamics. This study presents a novel physical model of landslide–forest interaction with an explicit consideration of tree failures. The flume utilizes tree elements that are designed to fail at calibrated bending moments to model the mechanical behaviour of forests during landslide impact. A new dimensionless number is introduced to characterize the ratio of landslide impact-induced bending moment to the bending resistance of tree elements. The performance of this dimensionless number is validated through a series of flume tests. Preliminary findings on the tree mechanical properties in controlling landslide mobility and new insights into nature-based landslide mitigation strategies will be discussed.
How to cite: Liu, H. and Leonardi, A.: Modelling landslide–forest dynamics with controlled tree breakage, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11364, https://doi.org/10.5194/egusphere-egu26-11364, 2026.
Submarine landslides at volcanic islands can generate tsunamis that pose a threat to coastal communities. Identifying potential landslides is therefore essential to estimate the tsunami impact. Among possible triggering mechanisms, submarine eruptions are an important source of instability because rapid cone growth can steepen and destabilize volcanic flanks. However, the evolution of submarine volcanoes is rarely monitored. An exception is the 2011-2012 submarine eruption south of El Hierro (Canary Islands), where repeated multibeam surveys captured rapid cone growth alternating with multiple collapse episodes. This survey time series provides a unique opportunity to quantify failure volumes and geometries and to evaluate 3D numerical simulations of slide deformation and the associated near-field ocean response.
First, we estimate collapse volumes and map erosion/deposition patterns by differencing successive bathymetric digital elevation models. Then, in order to simulate slide deformation and mobility, we use a 3D viscoplastic mixture approach implemented in OpenFOAM. The modeling strategy is validated against a laboratory benchmark of tsunami generation by a submerged granular collapse, including slide kinematics and free-surface time series.
At field scale, the numerical simulation of the largest collapse is initialized from the mapped failure geometry. In the absence of nearshore wave gauge data, the rheological parameters of the slide are calibrated to reproduce the observed erosion/deposition pattern. After matching the landslide runout and deposits, we use the numerical simulations to study the resulting free-surface response, focusing on wave generation, directionality, and nearshore amplification. Overall, we show how repeated seafloor mapping and 3D modeling can be combined to reconstruct submarine landslide dynamics and assess nearshore tsunami hazards at volcanic islands.
How to cite: Puig Montellà, E., Romano, A., Barajas Ojeda, G., Lozano Rodríguez, J. A., Vázquez, J. T., and Fraile Nuez, E.: From repeated seafloor mapping to 3D multiphase simulations: reconstructing submarine landslides and predicting near-field waves in the Canary Islands, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11073, https://doi.org/10.5194/egusphere-egu26-11073, 2026.
The purpose of this study is to develop a numerical model for landslide prediction in saturated poro-elasto-plastic media, which explicitly incorporates the compressibility of both solid and fluid constituents, alongside the porosity-dependent evolution of compressibility and permeability. While previous models have yielded valuable insights into the behavior of saturated porous media—typically relying on simplified assumptions that link effective stress to material properties—this work introduces a more comprehensive framework that integrates macroscopic deformation and microscopic volumetric responses in a unified manner. Specifically, the proposed model achieves full coupling of three primary field variables: the displacement of the solid skeleton, the intrinsic volumetric strain of the solid constituent, and the pore fluid pressure. This macro–microscopic coupling ensures a representation of porosity evolution and its feedback effects on the hydraulic and mechanical behavior of the medium. In this work, the numerical implementation of the macro–microscopic coupled mixed finite element formulation is first presented. Then, the model is extended to incorporate porosity-dependent compressibility and permeability. Finally, based on the proposed framework, the influence of solid and fluid constituent compressibility on slope deformation and collapse is systematically investigated and discussed.
How to cite: Liang, J.-Y.: A Macro-Microscopic Coupled Mixed Finite Element Model for Landslide Prediction in Saturated Porous Media with Compressible Constituents, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15679, https://doi.org/10.5194/egusphere-egu26-15679, 2026.
Climate change has significantly increased the frequency of rock-ice avalanches in alpine regions, yet their remote locations and abrupt nature have long hindered a deep understanding of their initiation mechanisms. This study investigates the mechanical and hydraulic processes triggering rock-wedge and rock-wedge-ice slides through advanced geotechnical centrifuge experiments (130-g), drawing insights from the 2000 Yigong landslide and the 2021 Chamoli rock-ice avalanche. By simulating freeze-thaw cycles (FTCs) in a temperature-controlled environment, we conducted comparative analyses between rock wedge models with and without glacier cover. The results demonstrate that frost heave and pore water pressure fluctuate parabolically with temperature, leading to progressive rock mass softening and stress redistribution. Notably, meltwater infiltration in the glacier-covered models significantly accelerated the failure process, by weakening the rock-ice bonding and increasing pore pressure along discontinuities. The experiments reveal that the transition from observable surface deformation to catastrophic failure occurs extremely rapidly, often in less than 20 seconds. These findings provide critical experimental evidence of thermo-hydro-mechanical coupling in high-altitude cryosphere hazards and identify high-amplitude fluctuations in stress and pore pressure as vital precursors for early warning and risk mitigation.
How to cite: Pan, Q.: Experimental Study on the Thermo-Hydro-Mechanical Coupling and Abrupt Initiation ofRock-Ice Avalanches via Centrifuge Modeling, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4475, https://doi.org/10.5194/egusphere-egu26-4475, 2026.
Understanding the stability of loess slopes under the combined effects of engineering activities and extreme rainfall is essential for sustainable land use and infrastructure development in loess regions under climate change. In this study, a 1:20 large-scale physical model test was conducted to investigate the multi-field responses and deformation–failure mechanisms of loess slopes subjected to coupled surcharge loading, slope excavation, and continuous rainfall. The spatiotemporal evolution of the stress, moisture, pore-water pressure, and deformation fields was systematically monitored throughout the entire loading–excavation–rainfall process. The results indicate that: (1) Engineering disturbances induce pronounced stress concentration zones within the slope, which are further intensified and migrate downward during rainfall infiltration. The maximum vertical stress exceeded 150 kPa in the late rainfall stage, reflecting substantial stress redistribution under combined actions. (2) Rainfall infiltration exhibits apparent spatial and temporal heterogeneity, with rapid saturation of the shallow soil layer and delayed water migration and pore-pressure buildup in deeper zones. After approximately 15 h of rainfall, pore-water pressure increased sharply, concentrating in the middle–lower part of the slope toe and significantly reducing effective stress. (3) Slope deformation and failure evolve progressively from local initiation to through-going instability, characterized by a rapid chain-type process of “shallow softening → shallow mudified sliding → toe-shear failure → flow-plastic and liquefied sliding.” Shallow flow slides dominate the early stage and serve as precursors to more profound instability. These findings reveal the intrinsic mechanisms of coupling between engineering disturbances and rainfall infiltration that control loess slope instability. The experimentally identified failure processes and critical response characteristics provide scientific support for sustainable slope management, early warning, and risk mitigation strategies in loess regions facing increasing extreme rainfall under climate change.
How to cite: Deng, L.: Multi-Field Responses and Failure Mechanisms of Loess Slopes under Engineering Disturbance and Extreme Rainfall: Implications for Sustainable Slope Management , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15626, https://doi.org/10.5194/egusphere-egu26-15626, 2026.
Shallow landslides triggered by heavy rainfall often occur in clusters in mountainous regions and pose serious hazards. Understanding how groundwater and soil moisture respond to rainfall is therefore crucial. This study draws on in-situ monitoring and capillary rise experiments to examine these processes. Using three years of continuous field observations, we analyzed the relationships among rainfall infiltration, soil volumetric moisture content, and groundwater level. In addition, 14 model tests were conducted to assess the influence of soil density and fine/coarse particle composition on capillary rise, quantify the correlation between rainfall intensity and groundwater level, and develop a predictive model for capillary rise height based on fine particle content in gravelly soils. Building on these results, a landslide stability prediction model that incorporates rainfall and groundwater dynamics were formulated. The findings indicate that: (1) Shallow groundwater on slopes shows periodic fluctuations, with each hydrological year comprising three phases: slow decline, rapid decline, and rapid rise. Groundwater depth is negatively and linearly correlated with rainfall, while the link between water-level rise after rainfall events and rainfall is weak; (2) The final stable height of capillary rise in residual gravelly soil follows a power function of fine-grained content. Higher fine-grained content produces greater stable heights, but all samples remained below 1.0 m, suggesting that groundwater has limited influence on upper soil moisture in these soils; (3) According to the stability prediction model, the critical rainfall threshold for slope failure is 81.8 mm/day, and the groundwater depth threshold is 0.73 m. The results provide a basis for early warning and risk mitigation of rainfall-induced shallow landslides in mountainous terrain.
How to cite: Chen, C., fu, Y., Liu, J., and Li, T.: Rainfall-Induced Shallow Landslides: Hydrological Response Analysis and Stability Prediction Model Based on Field Monitoring and Model Experiments, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2712, https://doi.org/10.5194/egusphere-egu26-2712, 2026.
The behaviours of dry granular flows involved in geophysical flows are typically described by rheological laws. While these models enable effective discrimination of distinct flow regimes, in-depth elaboration on the differentiating characteristics pertaining to various regimes remains lacking. In this study, an independently developed rate-controlled parallel-plate rheometer was employed to conduct rheological tests on glass bead samples with a diameter of 3 mm and varied initial solid concentrations (CV0), under constant pressure across 9 shear rates. Two novel indicators were introduced to distinguish different flow regimes, namely the scaling parameter (β) that reflects the exponential relationship between granular temperature (T) and inertial number (I), and apparent viscosity (ηapp). ηapp decreases with the reduction of CV0 and the increase of shear speed (N), exhibiting a typical shear thinning behaviour. Correspondingly, β decreases with decreasing CV0 and increasing N, which corresponds to the flow regime transition from the dense and slow quasi-static regime to the dilute and fast intermediate regime.
How to cite: Yao, T.: Scaling of Granular Temperature and Local Inertia Number of Dense Dry Granular Flow, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16723, https://doi.org/10.5194/egusphere-egu26-16723, 2026.
Abstract: This paper introduces a new, traction-based framework combining spectral element method (SEM) and material point method (MPM) for multiscale analysis of coseismic landslides. On a regional scale, SEM is employed to simulate seismic wave propagation, accounting for complex geological and topographical conditions. On the local scale, MPM is utilized to model the landslide failure process, capturing failure mechanisms and large deformations. SEM simulation generates traction forces at the local boundaries, which are prescribed to the MPM domain as seismic input. The traction forces coupling effectively addresses multi-scale seismic wave propagation challenges across different computational domains. The method is verified through simulations of point-source wave propagation. Using the actual geological and topographical conditions, the study analyses the characteristics and mechanisms of coseismic landslides at Po Shan Road. The results demonstrate that the proposed method can significantly reduce computational workload while maintaining accuracy, making it a suitable tool for rapid coseismic landslide analysis and hazard assessment.
Acknowledgement: The authors thank the support from State Key Laboratory of Climate Resilience for Coastal Cities at HKUST (ITC-SKLCRCC26EGP1), Hong Kong Research Grants Council General Research Fund 16219424 and Theme-based Research T22-606/23-R.
How to cite: Niu, J. and Wang, G.: Traction-based SEM-MPM Framework for Multiscale Coseismic Landslide Analysis, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10865, https://doi.org/10.5194/egusphere-egu26-10865, 2026.
Floods frequently transport hazardous debris of varying sizes and shapes—such as vehicles, wood, boulders, and construction materials—which complicate accurate flood modeling and prediction. To address this challenge, we propose a multiresolution framework that couples computational fluid dynamics (CFD) with the discrete element method (DEM) for multiphase flood simulation. The framework incorporates three modules: resolved, unresolved, and mixed-resolved-unresolved CFD-DEM, each designed to model debris at different scales. The resolved module captures detailed fluid–solid interactions for arbitrarily shaped objects, allowing high-fidelity simulation of floods carrying vehicles, wood, and boulders through forested areas. Object shapes can be digitized from scaled samples using X-ray CT or smartphone-based scanning. In contrast, the unresolved module enables full-scale simulation of debris-laden floods over complex terrains, supporting analysis of flood impacts on bridges and mitigation structures. Enhanced by GPU acceleration, this multiresolution CFD-DEM framework offers a unified approach to modeling multiscale, multiphase flood systems, improving the understanding and prediction of flood dynamics and mitigation strategies. As a novel contribution to flood modeling, the framework holds potential for broader applications in natural, engineering, and industrial contexts involving fluid–solid systems across scales. Acknowledgement: This research was supported by the NSFC Young Scientists Fund (Type C, No. 52508410).
Figure 1 Multiresolution multiphase CFD-DEM modeling of flood debris
How to cite: Kong, Y. and Xu, Q.: Multiresolution Modeling of Floods: Integrating Widely Graded and Arbitrary-Shaped Debris, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19545, https://doi.org/10.5194/egusphere-egu26-19545, 2026.
Coastal landslides and cliff instabilities are increasingly affecting the Adriatic coastline due to climate change-driven extreme events, long-term marine erosion and growing anthropogenic pressures. These processes pose significant threats to coastal infrastructure, ecosystems and public safety, highlighting the need for advanced monitoring, analysis and decision-support tools. Within this context, the Interreg Italy-Croatia RESONANCE project aims to enhance hydrogeological risk prevention and management in coastal areas through the integration of high-resolution surveying techniques, numerical modelling and innovative digital visualization approaches.
This contribution presents the main activities and preliminary results of a study focused on the characterization and analysis of coastal slope instabilities at selected pilot sites along the Adriatic Sea. Four representative coastal settings were investigated, encompassing different geological and geomorphological conditions and a range of instability mechanisms, including rockfalls, topples and structurally controlled failures affecting rocky cliffs.
Data acquisition followed a multi-sensor and multi-scale approach integrating UAV-borne laser scanning, close-range photogrammetry and UAV-based thermal imaging, complemented by detailed in situ geomechanical surveys. UAV laser scanning and photogrammetry enabled the generation of ultra-high-resolution three-dimensional point clouds and digital surface models, providing a robust basis for detailed geomorphological mapping and structural analysis of rock masses. Thermographic surveys supplied additional information on thermal anomalies related to moisture distribution, fracture connectivity and potential zones of weakness within the cliffs. Field-based geomechanical investigations focused on the characterization of discontinuity networks, including orientation, spacing, persistence and surface conditions, providing key parameters for stability analyses.
A particular emphasis was placed on multi-temporal surveys, which are essential for understanding the short- to medium-term evolution of coastal cliffs. Repeated UAV acquisitions allowed the detection of subtle morphological changes, the quantification of erosion and retreat rates, and the identification of localized instability processes driven by meteomarine forcing, rainfall events and extreme climatic conditions. These datasets offer valuable constraints for assessing the temporal dynamics of coastal instability and for identifying sectors characterized by increasing susceptibility to failure.
The high-resolution three-dimensional models derived from remote sensing were subsequently employed for numerical modelling aimed at investigating failure mechanisms and controlling factors. The modelling outcomes highlighted the key parameters governing cliff stability and provided insights into the potential impacts of climate-related changes, such as increased storm frequency and rainfall intensity, on coastal slope instability.
In parallel with surveying and modelling activities, the study contributed to the development of advanced digital tools based on virtual, augmented and mixed reality (VR/AR/MR), which represent a core innovation of the RESONANCE project. These tools integrate three-dimensional models, multi-temporal datasets and numerical simulation outputs into immersive and interactive environments, enabling intuitive visualization of coastal instability processes and realistic failure scenarios. Such platforms have strong potential to support risk communication and decision-making by improving the understanding of complex geomorphological dynamics.
Overall, the results demonstrate that the integration of multi-source remote sensing, numerical modelling and immersive visualization provides an effective and innovative framework for the analysis of coastal landslides, supporting improved assessment and management of hydrogeological risk along the Adriatic coastline.
How to cite: Ottaviani, F., Annibali Corona, M., Lazzari, M., Leucci, G., Morelli, S., Ružić, I., Stocchi, P., and Francioni, M.: Coastal Landslide Analysis within the RESONANCE Project, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14346, https://doi.org/10.5194/egusphere-egu26-14346, 2026.
Numerous slope failures have been observed in deep-cutting gorges in Southwest China triggered by rainfall events. In this study, model-based experiments were conducted to investigate the failure mechanism of a gently dipping accumulation slope subjected to intermittent rainfall. The physical model was constructed using soil samples prepared according to similarity theory and direct shear test data. Intermittent rainfall conditions were simulated through controlled surface runoff and basal water pressure applied at the slope’s base. Throughout the experiment, deformation, earth pressure, and pore pressure were monitored using an array of transducers.
The findings indicate that slope failure initiated at the toe region. This was followed by staged sliding that progressively extended the unstable zone toward the trailing edge. Continued rainwater infiltration led to increased pore pressure, reduced matric suction, and decreased effective stress along the bedrock interface, ultimately contributing to slope failure.
A numerical simulation was also conducted under various intermittent rainfall scenarios. The results reveal that intermittent rainfall significantly affects slope stability even during non-rainy seasons, with slope stability weakening notably after rainfall cessation. Under equivalent total rainfall during the rainy season, longer intermittent periods correlate with greater slope instability. The first rainfall event after a prolonged dry interval markedly reduces slope strength.
Rainwater tends to accumulate along the gently sloping bedrock surface, forming transient groundwater levels and influencing the slope’s seepage field. The infiltration process primarily weakens soil strength parameters, while seepage thrust within the saturated zone exerts minimal influence on the slope’s safety factor. As groundwater levels rise, the sensitivity of the safety factor to rainfall gradually diminishes. Rainfall accumulation on gentle slopes leads to localized regions of high pore water pressure, enhancing the slope’s water retention capacity. Moreover, the stability coefficient of gently dipping landslides exhibits minor fluctuations under intermittent rainfall, rendering them prone to creep-slip deformation.
How to cite: Zhong, W., Zhu, Y., and He, N. and the Wei Zhong: Deformation Mechanism of an Intermittent Rainfall-Induced Gently Dipping Accumulation Landslide, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10370, https://doi.org/10.5194/egusphere-egu26-10370, 2026.
Dense granular flows are pivotal in a range of geological hazards, such as landslides, fault slip zones, debris flows, and rock avalanches. However, the coupled thermo-mechanical characteristics that dominate their evolutionary processes remain inadequately clarified. In this research, ring shear tests were carried out under high normal stress conditions using nearly crush-resistant glass beads, aiming to explore the variations of velocity and temperature distributions during the shearing process. High-speed imaging combined with particle image velocimetry (PIV) was utilized to resolve the granular velocity field, while both infrared thermography and embedded thermocouples were employed to capture thermal signals across the shear zone. A distinct temporal discrepancy between mechanical and thermal responses was observed: in the shear initiation phase, particle velocities rose sharply, whereas the temperature remained almost constant. On the contrary, during the steady-state phase, the velocity profiles stabilized, while temperature continued to accumulate—particularly within the lower shear band. Furthermore, slow thermal evolution was detected in the upper quasi-static region, and the local heating at the thermocouple interfaces exceeded the infrared surface measurement results. These findings emphasize the cumulative and spatially heterogeneous features of frictional heat generation in dense granular flows, providing valuable references for the validation of thermo-mechanical models associated with dense granular flows. This study carries important implications for deciphering the physical mechanisms that govern the evolution of velocity and temperature in geological hazard-related flows.
How to cite: Ge, Y., Hu, W., and Li, Y.: Velocity and Temperature Profile Evolution in Dense Granular Flows, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17962, https://doi.org/10.5194/egusphere-egu26-17962, 2026.
Rainfall-induced debris slides pose a significant threat to lives and infrastructure in mountainous terrains. Recent increases in the frequency and intensity of debris slides in the Indian Himalayas have been attributed to both human activities and extreme rainfall. Although debris slides are generally shallow and of lesser volume, they result in substantial impacts, including road blockages, river aggradation, infrastructure damage, and considerable economic losses due to their significant numbers during extreme rainfall events. The failure mechanisms of rainfall-induced debris slides are complex, largely due to the involvement of soil–rock mixtures rather than pure soil or intact rock. This variability challenges conventional slope stability analysis and necessitates more refined, material-specific modelling approaches to accurately forecast and mitigate debris slide hazards. In this study, we present a slope stability assessment model developed based on laboratory-based reduced-scale flume experiments. We also design the model to simulate the relationship between rainfall input and the initiation of debris instabilities. To evaluate and calibrate the model, we simulate various debris slide scenarios at different scales: a laboratory-based reduced-scale flume experiment, a single debris slide event at the slope scale, and a group of rainfall-induced debris slides at the catchment scale, all from the Lesser Himalayan catchment in India. The calibrated model was then used to conduct a parametric study assessing the influence of various controlling parameters on debris slide initiation. Furthermore, the model also establishes critical rainfall Intensity–Duration (ID) thresholds for debris slide initiation, thereby strengthening the existing meteorological threshold-based early warning system in India.
How to cite: Dewrari, M. and Siva Subramanian, S.: Design of a stability assessment approach for rainfall-induced debris slides using physical modelling and multi-scale numerical simulations, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10144, https://doi.org/10.5194/egusphere-egu26-10144, 2026.
Three-dimensional (3D) geological modeling is a modern way to characterize subsurface conditions and support underground digital twins. An essential task is to effectively utilize all available site investigation data and quantify geological uncertainty. This paper presents a generic 3D probabilistic geological modeling framework to fuse multisource data and quantify and reduce geological uncertainty. Data from geophysical tests, boreholes, standard penetration tests (SPTs) and cone penetration tests (CPTs) are integrated utilizing Bayesian sequential updating and density-corrected k-nearest neighbors (kNN) interpolation techniques. Compared with standard kNN, the density correction mitigates bias from clustered data. This framework was applied to two large areas in Hong Kong, and demonstrated more-robust performance and higher computational efficiency than traditional methods. Step-by-step integration of different data sources improves model accuracy and reduces uncertainty, with borehole data contributing the most, followed by CPT and then SPT. In areas with limited borehole data but sufficient geophysical, SPT, or CPT data, the method still can accurately identify geological types. The resulting geological model enables reliable spatial-temporal settlement prediction considering geotechnical and geological uncertainties. The framework enhances the accuracy of 3D geological modeling for large-scale sparse data sites and supports interactive model updates when new data become available.
How to cite: Zhao, Z. and Zhang, L.: Three-Dimensional Geological Modeling with Multisource Data Fusion, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-9344, https://doi.org/10.5194/egusphere-egu26-9344, 2026.
This study focuses on a critical challenge: accurately calculating the weight of sliding masses with complex geometries. To address this issue, the study systematically examines the use of Monte Carlo integration in slope stability analysis. Conventional analytical methods, such as the slice method, frequently encounter limitations due to their reliance on simplistic assumptions under complex boundary conditions, resulting in suboptimal accuracy or computational inefficiency. In order to surmount these limitations, the present research employs the Monte Carlo integration method in combination with the bounding box technique in an innovative manner. The findings indicate that computational accuracy can be flexibly regulated by modifying the number of random samples. As the sample size increases, the error value decreases gradually and stabilises. When the sample count reaches the order of 10⁷, the relative error in volume calculation remains within 0.0061%. In the two- and three-dimensional slope models with irregular slope boundaries, this approach enables efficient calculation of the area and volume of sliding masses with arbitrary shapes. The present study has sought to compare and contrast the validity of Monte Carlo integration with that of traditional methods. The findings of this investigation have been such that Monte Carlo integration has been shown to maintain computational stability and efficiency, whilst also exhibiting superior adaptability to complex boundary conditions. The proposed methodology can be further extended to develop quantitative tools for landslide risk classification and early-warning threshold determination. This study proposes a novel technical approach for high-precision slope stability evaluation and provides essential theoretical foundations and practical support for decision-making in geological hazard prevention and control. The study demonstrates significant engineering applicability and shows promise for broader implementation.
How to cite: Xie, Q., Wang, Y., and Jie, Y.: Application of Monte Carlo Integral Method in Slope Stability Analysis, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2477, https://doi.org/10.5194/egusphere-egu26-2477, 2026.
Basal boundary conditions exert a fundamental control on the mobility of granular flows. Recent numerical simulations by Wang et al. (2025, Journal of Fluid Mechanics) demonstrated that dense granular flows over smooth or weakly rough beds develop a thin but highly active basal boundary layer. This basal layer exhibits velocity slip and enhanced particle agitation. It causes the velocity profile to deviate from Bagnold scaling and leads to increase in flow velocity, providing a physically grounded explanation for the high mobility observed in natural mass movements. Natural landslides are predominantly composed of non-spherical particles, whose shape-induced rotational constraints may significantly modify basal layer dynamics. However, the role of particle shape in controlling basal slip and near-bed kinematics remains poorly understood.
In this study, we investigate particle-shape effects on basal boundary-layer slip using discrete element simulations of dense granular flows down smooth and rough inclines. Particles are represented as superquadrics with shape exponent n=2,3,4,5, and 6, systematically transitioning from spheres to increasingly angular grains while preserving identical volume and aspect ratio (a:b:c=1:1:1). This numerical framework allows isolation of shape-controlled mechanical effects at the basal boundary. Building on recent advances in basal slip mechanics and contact-dominated friction weakening, we hypothesize that increasing particle angularity progressively suppresses basal slip by limiting particle rotation, strengthening force-chain structures, and increasing the effective thickness of the basal shear layer. In contrast, near-spherical particles are expected to promote rolling-dominated basal dynamics, leading to stronger basal slip and enhanced flow mobility. Preliminary results indicate a systematic transition in basal slip behavior and boundary-layer structure with particle shape, highlighting particle geometry as a key factor governing basal boundary conditions and mobility in granular landslides.
Reference
Wang, T., L. Jing, C. Y. Kwok, Y. D. Sobral, T. Weinhart, & A. R. Thornton. Basal layer of granular flow down smooth and rough inclines: kinematics, slip laws and rheology. Journal of Fluid Mechanics, 2025, 1025: A27
How to cite: Chen, Q. and Jing, L.: How particle shape controls basal slip and mobility in granular flows down smooth and rough inclines, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12415, https://doi.org/10.5194/egusphere-egu26-12415, 2026.
Tailings dams are major man-made hazards of landslides, ranking 18th among international disaster incidents. Earthquakes are one of the primary driving factors that induce tailings dam failures, accounting for 17.1% of the total global tailings dam failure incidents. Therefore, revealing the instability mechanism of tailings dams under seismic loading is of great practical significance. Through shaking table physical model tests, the failure evolution process of the tailings dam under different seismic amplitudes and frequencies was systematically analyzed, with a focus on exploring the dynamic response of pore water pressure, displacement, and acceleration. The correlation mechanism between the seismic response and frequency-domain characteristics of the tailings dam was revealed using the Acceleration Amplification Factor (AAF), Fast Fourier Transform (FFT), and Hilbert-Huang Transform (HHT) methods. The results show that the closeness between the seismic frequency and the natural frequency of the tailings dam significantly affects the intensity of the seismic response, with the most significant under the resonance effect. With the increase of seismic amplitude, the dominant frequency of the tailings dam shows a gradual attenuation trend. However, after the tailings dam is damaged, the dominant frequency gradually increases. This characteristic can be used as a precursor criterion for tailings dam instability. Furthermore, the critical seismic failure threshold was determined, and a prediction model for this threshold was proposed. Combined with the identified seismic failure threshold, the results of this study can provide a theoretical basis and quantitative reference for the seismic stability evaluation, seismic design optimization, and disaster early warning of tailings dams, and have important engineering applications for reducing the risk of tailings dam failure and ensuring the safety of mines and downstream areas.
How to cite: Liu, H., Zhang, C., Yang, C., and Ma, C.: Seismic response mechanisms of tailings dam under various loading amplitudes and frequencies: Frequency-domain analysis and critical threshold from shaking table model tests, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8616, https://doi.org/10.5194/egusphere-egu26-8616, 2026.
Anti-dip rock slopes have a wide development and distribution in the Sanjiang rivers, and their deformation and damage phenomena are particularly prominent among all slope problems in the region. Earthquake is an important dynamic factor to induce landslides, which often leads to large-scale landslide disasters. In this paper, a model test of a reduced scale similar material shaking table was designed and completed using the historical landslide at Zongrong on the left bank of the Jinsha River as an example. By loading different types of seismic waves as well as different frequencies and amplitudes, the deformation damage mechanisms of anti-dip rock slopes and the influence of structural surfaces were investigated. Test results show that there is an elevation amplification effect and skin effect on anti-dip slopes under strong seismic action, the larger the amplitude, the more obvious it is. The rate of increase of the slope acceleration amplification factor is influenced more by frequency than by amplitude. The maximum values of the acceleration amplification 0.2g-0.3g for different amplitude values. The presence of structural surfaces changes the dynamic response characteristics of slope, and there is a clear difference in the amplification effect of their thickness on seismic waves, as thicker sections are suppressed and thinner sections are amplified. Amplitude 0.3g-0.4g is the critical dynamic condition for slope cracking and 0.7g-0.8g is the critical dynamic condition for slope destabilisation damage. The slope damage process can he broadly divided into three stages: the formation of top-of-slope tension cracks and toe-of-slope shear cracks; the expansion of cracks and shallow block shear damage sliding-block toppling; the formation of the main slip surface of the shallow slope and slope damage.
How to cite: Gong, Y. and Heinz, K.: Dynamic response and failure process of anti-dip rock slope under strong earthquake, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2551, https://doi.org/10.5194/egusphere-egu26-2551, 2026.
Since 2020, heavy rainfall has triggered two intensely deforming landslide bodies on a slope in Chaotian District, China, showing a "upper-lower superimposed" spatial distribution. Currently, research on the instability mechanisms and dynamic evolution of such landslides remains relatively limited. This study comprehensively employs high-precision UAV mapping and FLAC3D-Massflow coupled simulation technology, and combines them with field investigation, trench profile analysis, and borehole stratum exploration to construct a 3D geomechanical model of the study area. On this basis, the instability mechanisms and dynamic evolution of potential landslides with spatial superimposition characteristics were analyzed. The results show that under heavy rainfall conditions, the stability coefficient of the upper landslide decreased from 1.043 to 0.961. It became unstable along the contact interface between crushed stone soil and phyllite and moved toward the lower landslide. Under the dual effects of impact load and colluvial load, the stability coefficient of the lower landslide dropped from 1.121 to 0.954, triggering shear failure at the soil-rock interface and forming a landslide disaster chain. Eventually, the landslide volume reached 75.5×104 m3, direct impact area 0.29 km2, and residential buildings on the opposite bank of the slope also faced direct threats. This study reveals for the first time the dynamic evolution mechanism of "impact-colluvial load coupling" in spatially superimposed landslides, and simultaneously proposes a 3D quantification and stability analysis method for impact loads of such superimposed landslides. The research results contribute to deepening the understanding of similar superimposed landslides and their disaster impacts.
How to cite: Ren, H.: Detailed investigation and potential instability analysis based on FLAC3D-Massflow: a case study of Majia landslide, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4607, https://doi.org/10.5194/egusphere-egu26-4607, 2026.
Slow-moving landslides exhibit persistent slow displacement that is commonly controlled by groundwater fluctuations and saturated–unsaturated conditions. This study employs an advanced unsaturated visco-hypoplastic constitutive model within a finite-element framework to simulate the time-dependent deformation of slow-moving landslides. Time-dependent behavior is introduced through a viscous strain-rate term, while suction effects and stress history are captured within the hypoplastic formulation. A time-deformation analysis is performed, considering seepage and the evolution of suction. To reduce computational demand, the visco-hypoplastic model is applied to the shear zone where deformation concentrates, whereas the remaining slope is treated as elastic. Most parameters are derived from standard laboratory tests, and the remaining time-related parameters are calibrated using monitored displacement time series. The idealized slope analysis results quantify the impact of groundwater level fluctuations on displacement rates and deformation patterns, while field slope validation demonstrates that the model can reproduce observed landslide behavior. The proposed framework contributes to the prediction of landslide evolution and informs landslide mitigation and management.
How to cite: Wang, B., Wang, S., and Wu, W.: Numerical Modeling of Slow-Moving Landslides with an Unsaturated Visco-Hypoplastic Constitutive Model, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15532, https://doi.org/10.5194/egusphere-egu26-15532, 2026.
Runout analyses are widely used to simulate the propagation of landslides and debris flows in order to predict deposition and flow heights for hazard assessment and risk management. Among the available approaches and methods, physically based numerical models require the definition of multiple input parameters and boundary conditions, including rheological properties and potentially unstable volumes. Especially in a predictive context (forward analysis), a key challenge relates to the assumptions adopted during the model parametrization to realistically simulate the material behavior, often resulting in a strong user dependence of the modelling outcomes. Particularly, this uncertainty can mask the predictive accuracy of the simulations, affecting both the spatial distribution of deposits and the assessment of potentially affected areas. Such limitations are significantly evident where site-specific soil properties or documented past events are not available, further increasing subjectivity and underlining the need for approaches that explore a wide range of scenarios.
In this study, a probabilistic framework based on a Monte Carlo approach is presented to evaluate runout simulations implemented in the software RAMMS::Debrisflow (Rapid Mass Movement Simulation:: Debrisflow). Instead of defining “best-fit” parameter sets, the Monte Carlo approach allows the analyses of a large number of simulations, each performed using an independent set of input parameters randomly sampled from defined statistical distributions. The framework is applied to assess potential mobilizations of a complex earth-slide system in the Granitztal (Carinthia, S Austria), which initially occurred in August 2023 following an extreme rainfall associated to the “Zacharias” storm that triggered multiple earth-slides and mudflows across the region. As the slope has not fully failed, it represents an ongoing hazard for residents and threatens the buildings located in the lower part of the slope.
Field investigations and multi-temporal monitoring were conducted using Electrical Resistivity Tomography (ERT) and UAV-derived data to provide spatially distributed information on the subsurface structure of the slope and surface morphologies, identifying features of progressive deformation and potentially mobilizable volumes. These datasets are used to constrain release volumes in the RAMMS simulations, allowing data-driven runout patterns within the explored scenarios. The resulting large set of simulations is analyzed statistically to derive runout metrics and to evaluate the spatial variability of predicted deposition heights. By including a broader range of scenarios, this study demonstrates the value of data-driven, probabilistic runout modelling in reducing user dependence and improving the robustness of predictive hazard assessment.
How to cite: Carraro, E., Andlinger, H., Christen, M., Marr, P., and Glade, T.: From storm-induced failure to runout simulations: A Monte Carlo-based probabilistic assessment of potential landslide scenarios in the Granitztal (Austria) , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20556, https://doi.org/10.5194/egusphere-egu26-20556, 2026.
Intensive rainfall events can lead to the accumulation of pore water pressure within clay-rich shear zones. Under undrained conditions, the reduced effective stress of shear-zone soil ultimately promotes slope failure. This study investigates rainfall-induced landslide initiation through both experimental and numerical approaches. A series of direct shear tests were performed on shear-zone soils to study their response to stress and pore pressure changes under a constant shear stress path. To simulate the initiation mechanism of the rainfall-induced landslide, a hypoplastic constitutive model for overconsolidated clays was employed. The simulation results reveal distinct failure patterns under varying rainfall scenarios, highlighting the critical role of pore pressure dynamics in controlling landslide stability.
How to cite: Kang, X., Wang, S., and Wu, W.: Instability of a Rainfall-Induced Landslide Driven by Pore Pressure Generation in the Basal Shear Zone, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16519, https://doi.org/10.5194/egusphere-egu26-16519, 2026.
Giant landslides and debris flows in mountainous regions, exacerbated by climate change, frequently form landslide-dammed lakes whose breaching can trigger catastrophic outburst floods. Current understanding relies heavily on post-event field investigations, laboratory experiments, and continuum-based simulations, leaving the multiphase dynamics of fluid–debris interactions across scales poorly quantified. To address this, we develop a novel multiresolution coupled Computational Fluid Dynamics (CFD) and Discrete Element Method (DEM) framework capable of simulating the entire disaster chain—from landslide motion and dam formation to overtopping failure and flood propagation. The framework integrates resolved, unresolved, and hybrid resolution schemes to capture multiscale particulate systems efficiently. Real-world topography and irregularly shaped grains (from gravel to boulders) are directly incorporated via STL files. Computational efficiency is enhanced through GPU acceleration and adaptive mesh refinement, enabling large‑scale simulations. In a preliminary test simulating a 2.9 km × 2.8 km × 0.8 km domain with approximately 1.5 million polydisperse particles, 500 s of real‑time dynamics were computed in 25 hours using an RTX 5090, demonstrating the framework’s capability to model full‑scale disaster chains with complex fluid–solid coupling. This work provides a quantitatively accurate tool for assessing disaster progression and hazard potential, representing a significant advance in geohazard modeling with broader applicability to multiscale, multiphase particulate systems in engineering and environmental sciences. Acknowledgement: This research was supported by the NSFC Young Scientists Fund (Type C, No. 52508410).
Figure 1 Multiresolution CFD-DEM modeling of landslide-dammed lake breaching-outburst flood disaster chains
How to cite: Kong, Y. and Fan, X.: Multiresolution Multiphase Modeling of Giant Landslide-Dammed Lake Breaching-Outburst Flood Disaster Chains, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16414, https://doi.org/10.5194/egusphere-egu26-16414, 2026.
Traditional methods for assessing the risk to linear engineering projects (e.g., pipelines, railways, power transmission lines, etc.) from landslides are constrained by the need for prior prediction of specific landslide geometries. This leads to complex processes and uncertain outcomes. This study proposes a fundamental paradigm shift: employing slope units as stable assessment units and directly evaluating their probability of overall instability as the hazard indicator. Furthermore, for the linear engineering segment traversing a given unit, its vulnerability and failure consequences can be predetermined and uniquely defined within the unit based on engineering attributes (e.g., crossing type, structural design parameters, socio-economic value), forming a "fixed-parameter" system. Consequently, the risk to linear engineering projects under landslide influence is simplified into a standardized formula: Unit Risk = Unit Landslide Probability (predicted) × Unit Linear Engineering Vulnerability (fixed) × Unit Linear Engineering Failure Consequence (fixed). The core advantages of this model lie in its generality and efficiency: 1) It is applicable to all types of mountainous linear engineering projects including pipelines, roads, railways, and transmission lines; 2) It is equally suitable for forward-looking risk assessment during the planning and design phase as well as for rapid risk screening during operation and maintenance; 3) By encapsulating complex uncertainties within the probabilistic assessment of the slope unit while standardizing vulnerability and consequence parameters, it transforms the evaluation process from "case-by-case judgment" to "standardized calculation". This method offers a promising novel pathway toward standardized and rapid assessment for managing the risk to linear engineering projects under landslide influence, holding significant application potential, particularly for the preliminary screening and systematic comparison of risks to long-distance projects under the influence of geohazards.
How to cite: Huang, L., Jing, H., Ren, X., and Deng, Q.: Efficient Quantification of Risk for Linear Engineering Projects under Landslide Hazards: A Novel Proposal Based on Slope Unit, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2116, https://doi.org/10.5194/egusphere-egu26-2116, 2026.
Many reservoir landslides tend to remain in a creep state under periodic water level fluctuations, with the sliding zone acting as the weakest structural layer controlling overall deformation. Understanding the creep behavior of sliding-zone soils under cyclic seepage pressure (CSP) and the associated mechanisms is therefore essential for assessing the long-term deformation and stability of reservoir landslides. In this study, seepage and triaxial creep tests were conducted to investigate the pore structure evolution and creep behavior of sliding-zone soils subjected to CSP. Computed tomography (CT) was employed to quantitatively characterize the pore structure, including porosity, pore size distribution, pore shape, and pore throat distribution. Results reveal that CSP promotes a more uniform spatial distribution of pores with predominantly flaky morphology, facilitating the formation of a connected pore network in which small-area pore throats serve as primary seepage pathways. Under CSP, the soil exhibits a distinct ‘‘stick-slip’’ creep behavior that accelerates the creep rate while reducing the total creep deformation. When the deviatoric stress is lower than the CSP amplitude, the creep response fluctuates markedly, whereas at stresses exceeding 900 kPa, the effect of CSP becomes negligible. These findings offer a new perspective on the creep mechanisms of reservoir landslides influenced by water level variations and establish a theoretical basis for precise evaluation of their long-term stability.
How to cite: Zhang, H. and Hu, X.: Pore-scale structure evolution and creep behavior of sliding-zone soil under cyclic seepage pressure, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6462, https://doi.org/10.5194/egusphere-egu26-6462, 2026.
Rainfall infiltration is a critical trigger for tailings dam instability, as the migration of the wetting front and the evolution of internal saturation directly govern the mechanical response and deformation behavior of the dam. This study establishes a representative cross-sectional model of a centerline-constructed tailings reservoir and employs FLAC3D for fluid–solid coupled numerical simulation, systematically investigating the dynamic distribution of saturation and deformation characteristics under continuous rainfall conditions. The simulation implements an extreme rainfall scenario with an intensity of 40 mm/d sustained for 80 days, focusing particularly on the time-history variations of saturation at the surface, 1 m, and 3 m depths in critical zones including the dam crest, dry beach area, upstream slope, and sediment retention structures. Results reveal a phased evolution of saturation under prolonged rainfall: during the initial phase (0–40 days), saturation increases rapidly to peak values (approximately 0.45), with surface zones reaching peak saturation earlier than deeper layers. Notably, the sediment retention dam exhibits excellent drainage performance, maintaining saturation below 0.1 throughout the 3 m depth after a slight initial increase. In the later phase (40–80 days), surface saturation slightly decreases (remaining below 0.45), while deeper layers continue to experience gradual saturation increase due to the dynamic equilibrium between continuous infiltration and internal drainage, leading to a distinctive distribution where internal saturation exceeds surface values. Monitoring data from dam slope positions show that downstream areas experience a 20–30% faster rise in saturation compared to upstream sections, attributed to the superposition of internal seepage flow. Displacement analysis indicates that sustained rainfall mainly induces settlement at the dam crest and upstream slope. When considering the saturation-induced softening effect of tailings, local displacement increments are positively correlated with changes in saturation. Through long-duration rainfall simulation, this research elucidates the coupled mechanism between wetting zone evolution and deformation response in centerline tailings dams under extreme conditions, providing essential data support for long-term stability assessment and early-warning indicator development for tailings dams.
How to cite: Han, X. and Zhang, C.: Rainfall Infiltration-Induced Saturation Evolution and Deformation Response of Centerline Tailings Dams: A Numerical Study, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-9155, https://doi.org/10.5194/egusphere-egu26-9155, 2026.
Earthquakes are one of the main causes of landslide disasters. The existing cavities in the slope will generate the effects of cavities under the action of earthquakes, seriously affecting the stability of the slope. Therefore, revealing the mechanism by which the effects of cavities caused by the action of earthquakes lead to the instability of the slope has significant practical significance. Through shaking table physical model tests and numerical simulation tests using the discrete element method, the development and destruction evolution process of cracks in the slope with cavities under different seismic amplitudes and frequencies were systematically analyzed. The amplification effect of the excess cavity gas generated by strong earthquakes on the displacement and acceleration of the slope was also discussed in detail. The research results show: The slopes with cavities failed under a vibration intensity of 0.5g at 10Hz. Due to the effect of the cavity, the excess cavity gas generated by it amplified the dynamic response of the surrounding rock mass, thereby intensifying the failure of the rock mass and the expansion of the cracks. Under strong earthquake conditions, the failure mechanism of the cavity-containing slope is that the fractured rock mass around the cavity continuously interacts with the excess cavity gas, thereby causing the rock mass to gradually deteriorate. The research results can further refine the deformation and failure mode of slopes under strong earthquakes, providing a reference for actual engineering projects and landslide prevention.
How to cite: jin, W., zhang, C., and wang, X.: The Impact of Cavity Effects on Slope Deformation and Failure Under StrongEarthquake Conditions, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11267, https://doi.org/10.5194/egusphere-egu26-11267, 2026.
Rainfall-induced landslides present significant hazards worldwide, particularly in regions experiencing intermittent storms. This study investigates the complex interactions between shear displacement (SD) and pore-water pressure (PWP) within a steep slate slope subjected to controlled rainfall conditions. Through a series of large-scale field experiments, we characterize the response of the slope across three distinct stages of deformation. Our findings reveal a bidirectional feedback mechanism, termed circular causality, wherein increases in PWP drive concurrent changes in SD, and vice versa, demonstrating that traditional linear models of slope failure are insufficient. Specifically, we identify four mesoscopic interaction modes between SD and PWP, highlighting how variations in soil moisture serve as reliable precursors for predicting abrupt slope deformations. These insights indicate that monitoring soil water content changes offers a more effective strategy for early warning systems in landslide-prone areas. Consequently, this study contributes to a deeper understanding of slope stability dynamics and provides essential guidance for the development of improved forecasting models and mitigation strategies in the context of climate variability.
How to cite: Zhang, C., Wang, L., and Fang, K.: Circular Causality in Rainfall-Induced Landslides: Bidirectional Feedback Between Shear Displacement and Pore-Water Pressure, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8658, https://doi.org/10.5194/egusphere-egu26-8658, 2026.
ABSTRACT
The canyon section of the upper Yellow River is characterized by complex geological conditions and frequent landslide hazards, which pose a cascading disaster threat to the cascade hydropower systems. This study takes the Likan Highway–Lijiaxia landslide as a typical case and systematically evaluates the risk of the landslide–surge–dam failure disaster chain through integrated multi-source remote sensing, time-series InSAR monitoring, material composition analysis, and multi-process coupled numerical simulation. Using more than 80 Sentinel-1A SAR images acquired between 2018 and 2023, a millimeter-scale deformation field of the landslide was derived using the SBAS-InSAR technique, revealing a maximum annual deformation rate of 24 mm/a at the landslide front and a cumulative deformation of 133 mm. Field investigations and laboratory tests identified that the landslide body consists mainly of Neogene mudstone breccia, with the slip zone rich in illite (content 18%–25%) and exhibiting low residual strength.
For disaster chain simulation, a fully coupled numerical model of “landslide motion – surge generation – dam response” was developed:
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The landslide motion module employs the Material Point Method (MPM) to simulate the dynamic process from slope failure to water impact, incorporating strain softening of the slip surface and debris fluidization.
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The surge generation and propagation module is based on the Volume of Fluid (VOF) method solving the 3D Navier–Stokes equations, implemented in FLOW-3D to simulate transient flow and capture air–water–solid interactions.
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The dam response module uses Fluid–Structure Interaction (FSI) to dynamically transfer hydrodynamic loads to a finite element dam model (ABAQUS), considering a concrete damaged plasticity constitutive model and nonlinear foundation contact.
Five sliding scenarios were simulated (volume: 1–10 million m³, velocity: 5–20 m/s). Under the extreme scenario (10 million m³, 20 m/s), the initial surge height reached 35–45 m, attenuating to 15–20 m at the dam face, with peak impact pressure of 250–320 kPa. Dynamic time-history analysis indicated that local areas of the dam may experience tensile damage (maximum damage factor D<sub>max</sub> = 0.15–0.22), though the overall stability safety factor remains above the code limit (F<sub>s</sub> > 1.05). Sensitivity analysis showed that sliding velocity has approximately 1.8 times greater influence on surge height than landslide volume.
The proposed framework of “integrated space–air–ground monitoring and multi-process coupled simulation” provides a quantitative risk assessment tool for the entire disaster chain—from landslide detection to dam safety evaluation—and offers critical technical support for disaster prevention decisions in hydropower projects along the upper Yellow River.
KEYWORDS: Upper Yellow River; InSAR; landslide material composition; surge simulation; fluid–structure interaction; disaster chain
Study Area Location Map
Geological Map of the Study Area
How to cite: huang, R. and wang, G.: Monitoring of Landslide Deformation in the Upper Reaches of China's Yellow River and Simulation of Full-Scale Disaster Surge-Induced Dam Breaches: A Case Study of Lijiaxia, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10643, https://doi.org/10.5194/egusphere-egu26-10643, 2026.
Predicting the transformation of earthquake-induced submarine landslides into dilute turbidity currents is critical for geohazard assessment, yet capturing the sediment suspension at the landslide interface remains a significant numerical challenge. This study presents a major methodological innovation by developing the Concentration Gradient Method (CGM) and integrating it into the SPLASH3D framework. The primary goal is to resolve the dynamic sediment remobilization triggered by seismic events with high fidelity, moving beyond the limitations of traditional rigid-interface models.
The numerical framework solves the three-dimensional incompressible Navier-Stokes equations combined with the Volume of Fluid (VOF) method for interface tracking. While the solver utilizes a standard Two-Step Projection Method, the originality of this research lies in the introduction of the CGM and the Discontinuous Bi-viscosity Model (DBM) during the predictor step. By implementing the newly developed CGM, we effectively bridge the landslide mass and the ambient fluid, transforming the traditionally rigid sediment-water boundary into a dynamic, concentration-dependent layer. This allows for the precise tracking of sediment particle suspension and settling mechanisms, which are governed by local concentration gradients.
Numerical results demonstrate that the diffusion coefficient (D) in the CGM is the governing parameter for the evolution of turbidity currents. We found that higher diffusion rates significantly increase the volume of suspended sediment and accelerate the flow front through enhanced momentum exchange at the interface. Furthermore, the model successfully captures complex turbulent structures and spiral-like diffusion patterns—physical features that are unresolvable in conventional single-phase or rigid-body models. This advanced simulation approach significantly improves the accuracy of modeling landslide propagation and deposition, providing robust numerical support for risk-informed design of offshore infrastructure and the quantitative reconstruction of historical seismic events.
How to cite: Chang, C.-H., Yeh, C.-H., and Wu, T.-R.: A Novel Concentration Gradient Method (CGM) for Modeling Sediment Suspension in Earthquake-Induced Submarine Landslides: Enhancing Predictive Accuracy in a 3D CFD Framework, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7916, https://doi.org/10.5194/egusphere-egu26-7916, 2026.
Posters virtual: Fri, 8 May, 14:00–18:00 | vPoster spot 3
EGU26-7212 | ECS | Posters virtual | VPS14
Understanding Coriolis effects in centrifuge modeling of high-speed dry granular flowsFri, 08 May, 14:15–14:18 (CEST) vPoster spot 3
Geotechnical centrifuge modeling provides an effective approach to reproduce prototype-relevant stress states for high-speed dry granular flows. Yet, in a rotating reference frame, the Coriolis acceleration induced by rapid granular motion can become comparable to the centrifugal acceleration, thereby markedly modifying run-out behavior and impact responses and complicating the interpretation of physical modeling results. This study integrates a suite of centrifuge model tests with discrete element method (DEM) simulations to systematically elucidate how Coriolis effects govern both the mobility of dry granular flows and their impact on rigid barriers. For run-out processes, a DEM framework incorporating both centrifugal and Coriolis accelerations is employed to compare granular mobility under three Coriolis configurations: dilative, compressive, and deflective conditions. The results indicate that the dilative Coriolis condition substantially enhances flow mobility and kinetic energy, whereas the compressive condition suppresses run-out and promotes flow densification. In contrast, under the deflective Coriolis condition, the sensitivity of the final run-out distance and overall flow scale to Coriolis effects is significantly reduced. This reduced sensitivity is attributed to two opposing deflection stages during propagation and deposition, suggesting a practical advantage for mitigating Coriolis-induced bias in centrifuge modeling. For impact processes, centrifuge experiments combined with DEM simulations are used to characterize granular impact behaviors on rigid barriers under different Coriolis conditions. The Coriolis effect has a limited influence on the peak magnitude of the total impact force, but it significantly alters the force time history and spatial distribution by modifying the velocity structure, flow thickness, and particle-scale momentum transfer. Notably, impact responses obtained under the dilative Coriolis condition are closer in force level to Coriolis-free reference cases, whereas the resultant force application point is comparatively insensitive to the Coriolis configuration. Overall, the results demonstrate that Coriolis effects should not be treated as a uniform experimental disturbance. Instead, they represent a key control factor whose influence depends on the specific quantities of interest. The findings provide methodological guidance for configuring centrifuge experiments and interpreting results in the modeling of high-speed dry granular flows, with explicit implications for both run-out and impact simulations.
How to cite: Zhang, B.: Understanding Coriolis effects in centrifuge modeling of high-speed dry granular flows, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7212, https://doi.org/10.5194/egusphere-egu26-7212, 2026.
