Investigating the release and flow of snow avalanches at the slope-scale using a unified model based on the material point method

Erosion and entrainment are critical processes in gravity-driven mass flows like snow avalanches, as they can significantly change the flow mass and momentum and thus affect the flow dynamics. In snow avalanches, snow cover can be considerably eroded but only partially entrained into the flow. Differentiating erosion and entrainment gives more accurate prediction of the increased flow mass and offers information on eroded snow cover remaining on the slope, but is challenging in practice. This study investigates snow avalanche erosion and entrainment with the material point method, focusing on exploring various erosion mechanisms, differences in erosion and entrainment, and their possible influences on runout distance. By using different mechanical properties for the flowing snow, distinct erosion patterns are observed and the corresponding temporal evolutions of entrainment, erosion, and deposition in the erodible bed are examined. Erosion and entrainment require an appropriate combination of snow friction and cohesion of the bed. If cohesion and/or friction are too low, the bed will naturally be unstable. On the other hand, highly cohesive and frictional bed will prevent erosion. For intermediate values, erosion and entrainment can be notable, and the amount of eroded snow shows a clear negative correlation with snow friction and cohesion while the entrained snow does not demonstrate a strong tendency. Furthermore, the release and erodible bed lengths are varied to study their effect on erosion and entrainment propensity. It is found that the increase in the lengths of the release zone and erodible bed leads to more erosion and entrainment as expected, but not necessarily to a longer runout distance. In our simulations, the release and erodible bed lengths are positively and negatively correlated with the runout distance, respectively. This implies that the runout distance can have opposite trends with erosion and entrainment, which might be closely related to the energy change of the simulated avalanches from the outlet of the erodible bed to the final deposit. Our results shed more light into the erosion and entrainment mechanisms and may contribute to improve related parametrizations in large-scale avalanche dynamics models.

Download Full-text

A Model-Based Simulation of CFRP-Steel Bond Failure Using the Material Point Method

Advances in Structural Engineering ◽

10.1260/1369-4332.14.5.777 ◽

2011 ◽

Vol 14 (5) ◽

pp. 777-787 ◽

Cited By ~ 1

Author(s):

Haydar Faleh ◽

Luming Shen ◽

Riadh Al-Mahaidi

Keyword(s):

Material Point Method ◽

Material Point ◽

Point Method ◽

Bond Failure ◽

Model Based

Download Full-text

The material point method for simulating dense snow avalanches over complex real terrain

10.5194/egusphere-egu21-6045 ◽

2021 ◽

Author(s):

Xingyue Li ◽

Betty Sovilla ◽

Chenfanfu Jiang ◽

Johan Gaume

Keyword(s):

Material Point Method ◽

Granular Flows ◽

Material Point ◽

Full Scale ◽

Point Method ◽

Constitutive Law ◽

Snow Avalanches ◽

Failure Patterns ◽

Snow Properties ◽

Modified Cam Clay

Various dynamics models can reproduce the motion of avalanches from release to deposition. These models often simulate a conceptual avalanche, adopt depth-averaged approaches and do not resolve variations along flow depth direction, and thus have clear limitations. This study presents three-dimensional, full-scale modeling of dense snow avalanches performed using the complex real terrain of the Vall&#233;e de la Sionne avalanche test site in Switzerland. We use the material point method (MPM) and a large-strain elastoplastic constitutive law for snow based on a Modified Cam Clay model. In our simulations, various and transient avalanche flow regimes are simulated by setting distinct snow properties. Snow avalanches are investigated from release to deposition. Detailed simulation results include the initial failure patterns, the mechanical behavior during the flow, and the characteristics of the final avalanche deposits. More specifically in the release zone, we can observe brittle and ductile fractures depending on the defined snow properties. During the flow phase, we monitor the temporal and spatial variations of snow density in the avalanche. In particular, cohesionless granular flows, cohesive granular flows, and plug flows are associated with snow fracture, compaction, and expansion. Finally, we can observe the structure of the avalanche deposit surfaces which show distinguishable differences in terms of smoothness, granulation, and compacting shear planes. This new model can offer a quantitative analysis for studying avalanches in different regimes and provide a powerful tool for exploring the dynamics of full-scale avalanches on complex real terrain, with high physical detail.

Download Full-text

Numerical modeling of snow avalanche dynamics based on the Material Point Method

10.5194/egusphere-egu2020-2153 ◽

2020 ◽

Author(s):

Xingyue Li ◽

Betty Sovilla ◽

Stephanie Wang ◽

Chenfanfu Jiang ◽

Johan Gaume

Keyword(s):

Numerical Modeling ◽

Material Point Method ◽

Maximum Velocity ◽

Flow Regimes ◽

Material Point ◽

Point Method ◽

Surface Shape ◽

Snow Avalanche ◽

Snow Avalanches ◽

Avalanche Dynamics

Snow avalanches are one of the most dangerous and catastrophic hazards in mountainous regions, which cause fatalities and property losses. Understanding the dynamics of snow avalanches is essential for designing safe and optimised mitigation measures. This study presents numerical modeling of snow avalanche dynamics, based on the Material Point Method (MPM) and an elastoplastic constitutive model for porous cohesive materials. MPM is a hybrid Eulerian-Lagrangian numerical method, which can simulate processes with large deformation, collisions and fractures. The elastoplastic model consists of an ellipsoid yield surface, a hardening law, and an associative flow rule. It enables us to capture the mixed-mode failure of snow including tensile, shear and compressive failure. Both ideal and real terrains are modeled in our study. By varying the properties of snow on the ideal slope, the model can reproduce four typical reported flow regimes, namely, cold shear, warm shear, warm plug and slab sliding regimes. In addition, surges and roll-waves are observed especially for flows in the transition from cold shear to warm shear regimes. The evolution of the avalanche front, the free surface shape and the velocity vertical profile show distinct characteristics for the different flow regimes. In addition to the snow properties, slope angle and path length are changed to investigate their effects on the maximum velocity, the run-out distance and the avalanche deposit height. The relation between the maximum velocity and the run-out distance obtained from our MPM simulations is analyzed along with data collected from literature. Furthermore, we benchmark the MPM model by simulating snow avalanches on real terrain. The evolution of the avalanche front position and velocity from the MPM simulations are quantitatively compared with the measurement data from past studies.

Download Full-text

A Hybrid Material Point Method for Frictional Contact with Diverse Materials

Proceedings of the ACM on Computer Graphics and Interactive Techniques ◽

10.1145/3340258 ◽

2019 ◽

Vol 2 (2) ◽

pp. 1-24 ◽

Cited By ~ 7

Author(s):

Xuchen Han ◽

Theodore F. Gast ◽

Qi Guo ◽

Stephanie Wang ◽

Chenfanfu Jiang ◽

...

Keyword(s):

Hybrid Material ◽

Frictional Contact ◽

Material Point Method ◽

Material Point ◽

Point Method

Download Full-text

Three-dimensional face stability analysis of shallow tunnels using numerical limit analysis and material point method

Tunnelling and Underground Space Technology ◽

10.1016/j.tust.2021.103904 ◽

2021 ◽

Vol 112 ◽

pp. 103904

Author(s):

Fabricio Fernández ◽

Jhonatan E.G. Rojas ◽

Eurípedes A. Vargas ◽

Raquel Q. Velloso ◽

Daniel Dias

Keyword(s):

Stability Analysis ◽

Limit Analysis ◽

Three Dimensional ◽

Material Point Method ◽

Material Point ◽

Point Method ◽

Face Stability ◽

Shallow Tunnels ◽

Dimensional Face

Download Full-text

A moving least squares material point method with displacement discontinuity and two-way rigid body coupling

ACM Transactions on Graphics ◽

10.1145/3197517.3201293 ◽

2018 ◽

Vol 37 (4) ◽

pp. 1-14 ◽

Cited By ~ 31

Author(s):

Yuanming Hu ◽

Yu Fang ◽

Ziheng Ge ◽

Ziyin Qu ◽

Yixin Zhu ◽

...

Keyword(s):

Rigid Body ◽

Least Squares ◽

Material Point Method ◽

Material Point ◽

Point Method ◽

Displacement Discontinuity ◽

Moving Least Squares

Download Full-text

Dam Breach Simulation with the Material Point Method

Computation ◽

10.3390/computation9020008 ◽

2021 ◽

Vol 9 (2) ◽

pp. 8

Author(s):

Chendi Cao ◽

Mitchell Neilsen

Keyword(s):

Material Point Method ◽

Mixture Theory ◽

Material Point ◽

Point Method ◽

Internal Erosion ◽

Dam Breach ◽

New Model ◽

Hencky Strain ◽

The Impact ◽

Soil And Water

Dam embankment breaches caused by overtopping or internal erosion can impact both life and property downstream. It is important to accurately predict the amount of erosion, peak discharge, and the resulting downstream flow. This paper presents a new model based on the material point method to simulate soil and water interaction and predict failure rate parameters. The model assumes that the dam consists of a homogeneous embankment constructed with cohesive soil, and water inflow is defined by a hydrograph using other readily available reach routing software. The model uses continuum mixture theory to describe each phase where each species individually obeys the conservation of mass and momentum. A two-grid material point method is used to discretize the governing equations. The Drucker–Prager plastic flow model, combined with a Hencky strain-based hyperelasticity model, is used to compute soil stress. Water is modeled as a weakly compressible fluid. Analysis of the model demonstrates the efficacy of our approach for existing examples of overtopping dam breach, dam failures, and collisions. Simulation results from our model are compared with a physical-based breach model, WinDAM C. The new model can capture water and soil interaction at a finer granularity than WinDAM C. The new model gradually removes the granular material during the breach process. The impact of material properties on the dam breach process is also analyzed.

Download Full-text