granular mass
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Author(s):  
Shaoyuan Pan ◽  
Yuya Yamaguchi ◽  
Anawat Suppasri ◽  
Shuji Moriguchi ◽  
Kenjiro Terada

AbstractThe present study proposes an MPM (material point method)–FEM (finite element method) hybrid analysis method for simulating granular mass–water interaction problems, in which the granular mass causes dynamic motion of the surrounding water. While the MPM is applied to the solid (soil) phase whose motion is suitably represented by Lagrangian description, the FEM is applied to the fluid (water) phase that is adapted for Eulerian description. Also, the phase-field approach is employed to capture the free surface. After the accuracy of the proposed method is tested by comparing the results to some analytical solutions of the consolidation theory, several numerical examples are presented to demonstrate its capability in simulating fluid motions induced by granular mass movements.


2020 ◽  
Vol 125 (10) ◽  
Author(s):  
Gordon G. D. Zhou ◽  
Kahlil F. E. Cui ◽  
Lu Jing ◽  
Tao Zhao ◽  
Dongri Song ◽  
...  

2020 ◽  
Author(s):  
Emmanuel Wyser ◽  
Yury Podladchikov ◽  
Marc-Henri Derron ◽  
Michel Jayboyedoff

<p>A granular collapse can be regarded as an idealized case of slumping, e.g., landslides. It consists in a sudden release, by the mean of an apparatus, of a dry granular mass initially contained which elasto-plastically collapses under its self weight and flows upon it reaches a new equilibrium.</p><p>We investigated such process by, i) performing numerical simulations and observing experimental evidences thanks to a newly designed apparatus that minimizes initial influences of the retaining walls over the collapse dynamic and, ii) developing an analytical formulation for the run-out distance of the granular mass in agreement with both experimental evidences and numerical solutions obtained by a home-made Material Point Method (MPM) implementation in Matlab based on the Generalized Interpolation Material Point (GIMP) variant. Finally, we further iii) showcase the suitability of the MPM solver to study strain localization problems and associated deformations considering homogeneous or inhomogeneous material properties for dry slumping processes.</p><p>We report an excellent agreement of the analytical solution with the experimental data. However, numerical solutions are in a similar range of validity but tend to overestimate the runout distance of the collapse. Nevertheless, large deformations induced by the elasto-plastic collapse are well captured by the solver. In addition, we report similar runout distances regardless for elasto-plastic constitutive relation. We finally demonstrate the importance of heterogeneities over the strain localization and the role of initial geometry in the non-linear behavior of the slumps. Moreover, this also establishes MPM as a relevant numerical framework to address fundamental issues for the geomechanics of slumping.</p>


2018 ◽  
Vol 13 (6) ◽  
pp. 1433-1450 ◽  
Author(s):  
Amir Ahmadipur ◽  
Tong Qiu
Keyword(s):  

2016 ◽  
Vol 806 ◽  
pp. 234-253 ◽  
Author(s):  
K.-L. Lee ◽  
F.-L. Yang

This work presents an asymptotic analysis for the propagation and arresting process of a two-dimensional finite granular mass down a rough incline in a shallow configuration. Bulk shear stress and arresting mechanism are formulated according to the coherence length model that considers momentum transport at a length scale over which grains are spatially correlated. A Bagnold-like streamwise velocity and a non-zero transverse velocity are solved and integrated into a surface kinematic condition to give an advection–diffusion equation for the bulk surface profile, $h(x,t)$, that is solved using the matched asymptotic method. These flow solutions are further employed to determine composite solutions for a flow-front trajectory and a local coherence length, $l(x,t)$, which reveals smooth growth of $h(x,t)$ and $l(x,t)$ from zero at the propagating front with $l(x,t)\ll h(x,t)$. At the rear, $h(x,t)$ vanishes but $l(x,t)$ asymptotes to a constant that depends on inclination angle. According to the arresting mechanism, the location where $l(x,t)\sim h(x,t)$ is solved to the leading order to locate the deposition front so that its propagation dynamics can be derived. A finite flow arrest time, $T_{d}$, and the corresponding finite run-out distance, $L_{d}$, are evaluated when all the flowing mass has passed the deposition front and are employed to construct a modified front trajectory with the deposition effect. The predicted run-out distance and front trajectory profile compare reasonably well with experimental data in the literature on inclinations at angles higher than the material repose angle.


2016 ◽  
Vol 90 (3) ◽  
pp. 988-998 ◽  
Author(s):  
ZHOU Gongdan ◽  
Nigel G. WRIGHT ◽  
SUN Qicheng ◽  
CAI Qipeng

2015 ◽  
Vol 52 (12) ◽  
pp. 2113-2133 ◽  
Author(s):  
Francesco Federico ◽  
Chiara Cesali

Several empirical relationships allowing a preliminary estimate of debris flow runout distances have been proposed to correlate the runout length to the volume of the sliding granular mass, delimit potentially hazardous areas, and design safeguarding measures. To overcome their large variability and define their fields of applicability, an energy-based model, predicting debris flow mobility, is developed. The power balance of a granular mass sliding along two planar surfaces is written by taking into account the volume of the debris mass, the slopes of the sliding surfaces, an assigned interstitial pressure, the possible mass variation along the motion, the energy dissipation due to the grain inelastic collisions (“granular temperature” within a basal “shear layer”), and friction. A system of ordinary differential equations is obtained; its numerical solution allows, through parametrical analyses: (i) highlighting of the role of physical and mechanical parameters on the runout distance, such as grain size material, interstitial pressures, grain collisions, and erodibility of the crossed channel; and (ii) defining of the favourable conditions for debris flows mechanism generation. Finally, through the back-analysis of some cases, an original relationship to estimate the runout length, as well as to interpret the results of the empirical formulas, is proposed.


Author(s):  
Giovanni B. Crosta ◽  
Mattia De Caro ◽  
Giorgio Volpi ◽  
Fabio De Blasio ◽  
Silvia Imposimato ◽  
...  
Keyword(s):  

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