Landslide-generated Waves Research Articles

Experimental Study on Landslide-Generated Waves Overtopping in Reservoirs with Arch Dams

Experimental Study on Landslide-Generated Waves Overtopping in Reservoirs with Arch Dams

Landslide-generated wave simulation using coupled multi-phase flow and Boussinesq-type models

The effect of landslide-generated tsunami waves on coastal areas can be initially understood through a numerical simulation. Moreover, an efficient numerical simulation would be beneficial for predicting tsunami waves. However, a single numerical model that can capture the landslide and wave propagation is still impractical, especially in a large-scale domain. A domain-partitioning technique or coupling model would be more practical. This paper reports a numerical study of a landslide-generated wave, which uses a multi-phase CFD model for the landslide phenomena and a surface wave model based on Boussinesq-type equations for wave propagation. The proposed coupling model that sits between the multi-phase CFD and wave models validated by laboratory experiments is shown to be effective. The computation domain of the CFD model can be defined as small as it covers the impacted area of the landslide. The rest of the domain can be handled by the wave model that propagates the wave accurately with a low computation cost.

Three-Dimensional Simulations of Subaerial Landslide-Generated Waves: Comparing OpenFOAM and FLOW-3D HYDRO Models

AbstractThe recent destructive landslide tsunamis, such as the 2018 Anak Krakatau event, were fresh reminders for developing validated three-dimensional numerical tools to accurately model landslide tsunamis and to predict their hazards. In this study, we perform Three-dimensional physical modelling of waves generated by subaerial solid-block landslides, and use the data to validate two numerical models: the commercial software FLOW-3D HYDRO and the open-source OpenFOAM package. These models are key representatives of the primary types of modelling tools—commercial and open-source—utilized by scientists and engineers in the field. This research is among a few studies on 3D physical and numerical models for landslide-generated waves, and it is the first time that the aforementioned two models are systematically compared. We show that the two models accurately reproduce the physical experiments and give similar performances in modelling landslide-generated waves. However, they apply different approaches, mechanisms and calibrations to deliver the tasks. It is found that the results of the two models are deviated by approximately 10% from one another. This guide helps engineers and scientists implement, calibrate, and validate these models for landslide-generated waves. The validity of this research is confined to solid-block subaerial landslides and their impact in the near-field zone.

An integrated numerical model for landslide-generated waves: a case study of the Gongjiafang landslide, Three Gorges Reservoir, China

ABSTRACT Landslide is a frequent geological hazard in the Three Gorges reservoir area of China. Impulse waves could be created and cause substantial damage if the landslide collides with a water body. A nonlinear shallow water equation in combination with a progressive landslide model is proposed to simulate this catastrophic disaster. The proposed approach is distinguished by rapid calculation, less computational burden, and high practical value. By simulating the 2008 Three Gorges Reservoir Gongjiafang landslide and the subsequent impulse waves, we illustrated and validated this methodology. The initiation and motion processes of the landslide, as well as the generation, propagation, and run-up processes of impulse waves, were thoroughly performed. The simulation results were in good agreement with the field survey data, demonstrating the viability of the proposed approach for simulating the impulse waves triggered by landslide events. This numerical approach is beneficial for engineers to perform a preliminary estimation of landslide-generated waves and further facilitate the prevention and mitigation of geological hazards.

The effects of dispersion and non-linearity on the simulation of landslide-generated waves using the reduced two-layer non-hydrostatic model

The effects of dispersion and non-linearity on the simulation of landslide-generated waves using the reduced two-layer non-hydrostatic model

Pressure Characteristics of Landslide-Generated Waves on Bridge Piers

In a reservoir area, landslides can generate waves that pose a significant threat to bridge piers, endangering both property and human safety. This study utilized three-dimensional water tank experiments to simulate the generation of landslide-induced waves and their impact on bridge piers located on both riverbanks. The analysis focused on the types and distribution patterns of wave pressures on bridge piers. The results reveal the following key findings: (1) The results show that the wave pressures on the piers can be classified into two types: Pulsating pressure (Ppu) and Resonance pressure (Pre). Ppu represents the pressure generated during the wave action process. Ppu closely corresponds to the wave height-time process, with frequencies ranging from 0.2 to 0.5 Hz. Pre occurs prior to Ppu. Pre represents high-frequency vibrational waves generated when bridge piers resonate during wave action. Pre is observed primarily in deep water conditions and on the opposite riverbank, with frequencies ranging from 300 to 900 Hz. (2) On the bridge piers of the opposite riverbank, Ppu exhibits a nearly vertical distribution along the water depth, while on the same side, Ppu exhibits a sawtooth-like decrease along the water depth. Ppu increases with greater landslide volume and steeper landslide angles, and the maximum wave pressure distribution occurs near the water surface. (3) The distribution of Pre/Ppu along the water depth exhibits three forms: multiple-peak, single-peak, and no-peak, with the maximum positions for all conditions of Pre/Ppu occurring at approximately one-third of the water depth from the surface (Y/h=0.3). Finally, predictive formulas for the maximum wave pressures are provided.

The Momentum Transfer Mechanism of a Landslide Intruding a Body of Water

Landslide-generated waves occur as a result of the intrusion of landslides such as mud flows and debris flows into bodies of water such as lakes and reservoirs. The objective of this study was to determine how the momentum is transferred from the sliding mass to the body of water on the basis of theoretical analysis and physical model experiments. Considering the viscoplastic idealization of natural landslides, the theoretical model was established based on the momentum and mass conservation of a two-phase flow in a control volume. To close the theoretical equations, slide thickness and velocity passing through the left boundary of the control volume were estimated by lubrication theory, and the interaction forces between the slide phase and water phase, including hydrostatic force and drag force, were given by semiempirical equations fitted with experimental data obtained using the particle image velocimetry (PIV) technique. The near-field velocity fields of both the sliding mass and the body of water, as well as the air–water–slide interfaces, were determined from the experiments. The theoretical model was validated by comparing the theoretical and experimental data of the slide thickness and slide velocity, as well as the momentum variations of the two phases in the control volume.

Temporal Prediction of Landslide-Generated Waves Using a Theoretical–Statistical Combined Method

For the prediction of landslide-generated waves, previous studies have developed numerous empirical equations to express the maximums of wave characteristics as functions of slide parameters upon impact. In this study, we built the temporal relationship between the wave characteristics and slide features. We gave specific insights into impulse waves generated by snow avalanches and mimicked them using a buoyant material called Carbopol whose density is close to that of water. Using the particle image velocimetry (PIV) technique, the slide’s temporal velocity field and thickness, as well as the temporal free water surface fluctuation, were determined experimentally. Using a statistical method denoted as panel data analysis, we quantified the temporal wave amplitude from the time series data of the thickness and depth-averaged velocity of the sliding mass at the shoreline. Then, the slide’s temporal thickness and velocity at the shoreline were estimated from the parameters of the stationary slide at the initial position, based on the viscoplastic theory. Combining the panel data analysis and the viscoplastic theory, the temporal wave amplitudes were estimated from the initial slide parameters. In the end, we validated the proposed theoretical–statistical combined predictive method with the support of experimental data.

A prediction model for the rockslide-generated wave amplitude under the condition of bedrock mass breakup

Landslides along coastlines and rivers can cause landslide-generated waves and pose a threat to the offshore banks, navigation vessels and coastal buildings. The maximum amplitude of the landslide-generated wave, which is strongly related to the size and geometry of the landslide and gradually decreases with the increase of the propagation distance, is one of the important indexes to evaluate the secondary hazard caused by landslides. The fragmentation of rockslide has an influence on the effect of rockslide on water body. This study proposes a relationship between the maximum rockslide-generated wave amplitude and the number of fragmentation blocks which is defined to present different degrees of landslide bedrock mass breakup. The computational fluid dynamics (CFD) numerical method is used to simulate the whole process of landslide and wave propagation. The orthogonal array experiment algorithm is used to design the numerical simulation schemes. The Gauss-Newton algorithm is adopted to analyze the results and elect the optimal model with the strongest correlation. A series of conducted physical model experiments prove the applicability and accuracy of the optimal model. This optimal numerical model can offer a reference for rockslide-generated wave analysis when considering bedrock mass breakup.

A Non-Hydrostatic Model for Simulating Weakly Dispersive Landslide-Generated Waves

The aim of this study is to develop an efficient numerical scheme that is capable of simulating landslide-generated waves. The numerical scheme is based on the one-layer non-hydrostatic (NH-1L) model, a phase-solving model that can account for weakly dispersive waves. In this paper, the model is extended to include a time-varying solid bed. This NH-1L scheme is very efficient because, at each time step, only a tridiagonal Poisson pressure matrix needs to be solved. In this study, the capability of the NH-1L scheme to simulate landslide-generated waves is demonstrated by executing two types of landslide motion: constant speed and with acceleration and deceleration. Validation was performed using analytical solutions of the linear weakly dispersive (LWD) model, as well as experimental data. The NH-1L model was capable of describing the generation and propagation of water waves by a submarine landslide from relatively intermediate water to shallow water depths.

A new predictive equation for estimating wave period of subaerial solid-block landslide-generated waves

ABSTRACT In the aftermath of the deadly 2018 Anak Krakatau tsunami (Indonesia) and associated confusions over its modeling and generation mechanism, there has been an urgent need for further studies to improve our understanding of landslide-generated tsunamis. Two important factors in accurate modeling of landslide tsunamis are the wave period and the initial wave amplitude. Here, we apply a physical modeling approach and develop an empirical equation to predict the dominant wave period generated by solid-block subaerial landslide tsunamis. Fifty-one laboratory experiments are conducted at different water depths and using four different concrete blocks for the sliding masses. The results are consequently employed to derive a predictive equation for the wave period of solid-block subaerial landslide tsunamis. An innovation of this study is that we apply data from different scales (laboratory and field scales) to produce our predictive equation. For field data, the data from the 2018 Anak Krakatau event is used. We compared our predictive equation with other previously-published equations. To confirm the validity of our predictive equation, it is applied for the prediction of the wave period of an independent landslide tsunami event whose data was not used for the derivation of the equation.

A Lagrangian–Eulerian procedure for the coupled solution of the Navier–Stokes and shallow water equations for landslide-generated waves

This work presents a partitioned method for landslide-generated wave events. The proposed strategy combines a Lagrangian Navier Stokes multi-fluid solver with an Eulerian method based on the Boussinesq shallow water equations. The Lagrangian solver uses the Particle Finite Element Method to model the landslide runout, its impact against the water body and the consequent wave generation. The results of this fully-resolved analysis are stored at selected interfaces and then used as input for the shallow water solver to model the far-field wave propagation. This one-way coupling scheme reduces drastically the computational cost of the analyses while maintaining high accuracy in reproducing the key phenomena of the cascading natural hazard. Several numerical examples are presented to show the accuracy and robustness of the proposed coupling strategy and its applicability to large-scale landslide-generated wave events. The validation of the partitioned method is performed versus available results of other numerical methods, analytical solutions and experimental measures.

Numerical simulation of landslide-generated waves using a SPH-DEM coupling model

Landslide-generated waves are natural disasters that have raised the attention and concerns of researchers and engineers during the past decades. Since landslide-generated waves involve complex processes such as the impact of landslides, wave generation, and propagation, traditional numerical methods cannot capture this process well. Based on Darcy's law, this study proposed a coupled algorithm of smooth particle hydrodynamics (SPH) and discrete element method (DEM) to deal with the interaction between particles and fluids at the macroscopic scale. The interrelationship between fluid permeation velocity and pressure in solids is considered in the coupled algorithm. The FORTRAN language established the landslide-generated surge wave model under the SPH-DEM fluid-solid coupling framework. The surge waves generated by underwater submerged deformable landslides and the high-speed unsubmerged deformable landslides were simulated as typical landslide cases in this study. Meanwhile, the effectiveness of the coupling method is verified by comparison with experimental data. The simulation results of the current model agree well with the experimental data or simulation results in the previous literature. Therefore, the SPH-DEM model can forecast the impacts of landslides-generated waves.

The Motion and Deformation of Viscoplastic Slide while Entering a Body of Water

Landslide-generated waves are hazards that, commonly, exist in the natural world. The motion and deformation of a submerged landslide significantly affect the efficiency of the momentum transfer, between the slide material and the water body, and, thereby, dominate the characteristics of the associated waves. Therefore, investigating how the submerged sliding mass is moved and deformed is of great importance, not only for understanding the physical mechanism behind the slide–water interaction but also for optimizing the predictive models of the wave characteristics. In this study, we assumed the landslide as a viscoplastic fluid and used an ideal viscoplastic material, called Carbopol, to mimic a natural landslide, at the laboratory scale. We, first, determined the coordinates of three control points, including the frontal point, deepest point, and center of mass, so as to quantify the time evolution of the submerged slide motion. We, then, fit the maximums of the coordinates of the control points with an integrated parameter of the incoming landslide, with the support of experimental data. Results indicated that not only the wave features but also the submerged slide motion can be quantified by the slide parameters on impact.

The Effect of River Channel Characteristics on Landslide-Generated Waves and the Dynamic Water Pressure of the Dam Surface

In a reservoir area, impulsive landslide surges induced by slope failure may pose huge damage to the dam and the lives in the shoreline areas, which are greatly affected by river channel characteristics. In this study, water depth, the width of the water surface, and the bending angle of river channel were chosen as the main influencing factors. The numerical method was used to investigate the influence of river channel characteristics on wave propagation and the distribution of dynamic water pressure on the dam surface. The effect mechanism was analyzed, and a prediction model considering river channel characteristics for the propagation wave height was established. Results show that water depth and the bending angle of the river channel play a positive role in the attenuation of the energy carried by landslide surges. The width of the water level mainly influences the propagation of impulse waves in the far-field area. The river channel characteristics affect the value of the dynamic pressure on the dam surface but have a minor effect on dynamic pressure distribution. The distribution of dynamic pressure on the dam is greatly influenced by the distance between the dam site and the place where the landslide occurs.

Impact of variation of size of the initial release mass in the dynamics of landslide generated tsunami

When debris flows, landslides, or any gravitational mass flows hit closed or partially open water sources such as seas, oceans, fjords, hydraulic reservoirs, mountain lakes, bays, and landslide dams, it results in tsunami (impulse water waves) by transforming their impact energy to water body, potentially causing damages of infrastructures and human casualties both near field and the distant coastlines. The intensity of hazard depends on the scale, location and process of the landslide, and also on the reservoir volume and topography that surrounds it. Volume or size of the initial release mass that fails and slides along a slope is one of the dominant factors to determine the degree of splash, propagating speed and the amplitudes of the fluid waves, and potential dam breach or water spill over. Here, we numerically integrate the two-phase mass flow model [Pudasaini S. P., J. Geophysi. Res. 117 (F03010), 2012] for quasi-three-dimensional, high-resolution simulation results with variation of size of the two-phase initial landslide or debris both longitudinally and laterally. In our numerical experimental results, we observe fundamentally different solid and fluid evolution and wave structures in the reservoir. There are also significant differences in the flow dynamics of solid under water for different volumes of the release mass by extending or contracting the base area along downslope and/or cross-slope directions. The simulation results show that tsunami amplitudes and run out extents are rapidly increased when the volume of the initial release mass in the form of a triangular wedge is increased by increasing the base area through the increment of the length and breadth of the release base. This study can be useful to develop and implement tsunami hazard mitigation strategies to enhance public safety and reduce potential loss due to landslide-generated wave hazards.

Wave types and energy conversion of impulse waves generated by landslides into mountain reservoirs

Subaerial landslides sliding into shallow water are physically modeled in a three-dimensional wave basin. The generated impulse waves are highly nonlinear, and a large-scale splash zone is formed above the waves. Such impulse wave characteristics are different from those from landslides into deep water that are completely submerged after sliding. The recorded wave profiles included three wave types, namely nonlinear oscillatory wave, nonlinear transition wave and bore-like wave, mainly depending on the relative slide thickness and slide Froude number at impact. Bore-like waves were possible produced only by landslides into shallow water in three-dimensional experiments. The conversion rate of landslide kinetic energy at impact into the wave train energy is 1 to 18%. Energy conversion characteristics are compared with other two- and three-dimensional studies on landslide-generated waves and the results are discussed.

Numerical Simulations of Tsunami Wave Generation by Submarine Landslides: Validation and Sensitivity Analysis to Landslide Parameters

Abstract Submarine landslide-generated waves have been responsible for significant damage to coastal communities worldwide. Despite this, the existing knowledge on the mechanism of the phenomenon i...

Analysis and Modelling of Ship Manoeuvring Simulation in Landslide-Generated Waves

The geological conditions of the Three Gorges Reservoir Region are complex and changing, and large- and medium-sized landslides are widely distributed. When a high-speed moving landslide enters the water, the water is significantly disturbed, and a landslide-generated wave will be formed, which will spread along the upstream and downstream of the river, causing significant threats and destruction to the hydraulic structures and the navigation of ships. Based on the typical rock landslide parameters and fracture development, we establish a three-dimensional physics experimental model of the bending section of the landslide-generated wave in the Three Gorges Reservoir Region. This paper primarily studies the variation law of the first wave height of landslide-generated waves with the width, height, and water entry velocity of the landslide body and then provides an empirical formula for the first wave height of landslide-generated waves in the curved section of the Three Gorges Reservoir Region. The ship rolling motion equation in the landslide-generated water area is analysed and established systematically. Additionally, the ship manoeuvring motion model in the landslide-generated water area is built. This paper explains the variation characteristics of ship turning tracks at different sailing speeds and sailing positions and proposes a basis to determine the navigation safety of ships in this area, thus providing new theoretical and technical support for the risk assessment of navigation of ships in the reservoir area.

Geometry-Based Preliminary Quantification of Landslide-Induced Impulse Wave Attenuation in Mountain Lakes

In this work, a simple methodology for preliminarily assessing the magnitude of potential landslide-induced impulse waves’ attenuation in mountain lakes is presented. A set of metrics is used to define the geometries of theoretical mountain lakes of different sizes and shapes and to simulate impulse waves in them using the hydrodynamic software Flow-3D. The modeling results provide the ‘wave decay potential’, a ratio between the maximum wave amplitude and the flow depth at the shoreline. Wave decay potential is highly correlated with what is defined as the ‘shape product’, a metric that represents lake geometry. The relation between these two parameters can be used to evaluate wave dissipation in a natural lake given its geometric properties, and thus estimate expected flow depth at the shoreline. This novel approach is tested by applying it to a real-world event, the 2007 landslide-generated wave in Chehalis Lake (Canada), where the results match well with those obtained using the empirical equation provided by ETH Zurich (2019 Edition). This work represents the initial stage in the development of this method, and it encourages additional research and modeling in which the influence of the impacting characteristics on the resulting waves and flow depths is investigated.