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 Resources: Publications and Reports

In this section you can find publications and reports on the fundamental research on sand cutting under water.
This research includes the research into sand cutting with large blade angles and deviated blade angles (snow plough effect).

The research started in 1983 and is still going on.



Home / Sand Cutting /

    27 - Discrete Element Method Modelling of Sand Cutting (1199)

Discrete Element Modelling (DEM) is a method which is designed to simulate the behaviour of a material

by modelling the interactions between discrete elements i.e. particles. The mechanical interactions between

particles and also between particles and the walls in are modelled by springs, dash-pots and friction sliders.

The properties of the material and interactions (Poisson's ratio, shear modulus and density, coefficients of

restitution, rolling and static friction) relate to the particle properties and not to the bulk properties. If DEM

(using software like EDEMTM & PFCTM) is reliable by validation with analytical models, it will have many

applications in dredging, specifically for investigating underwater cutting processes in sand, clay and rock.

Since people have no real experience with this method in dredging, the first step is to model a number of

well-known examples like passive earth pressure and the cutting of dry sand and compare the simulation

results with the analytical solutions. During this first step the relation between particle and bulk properties

has also been investigated. Since the EDEMTM software does not yet contain a code to calculate porosity

changes and pore water pressure (without coupling with CFD), this is implemented during a second step.

The final target of this study is to use the DEM software to possible modify Miedema and Evans analytical

solutions for sand and rock cutting at 3000 m water depths, but in the future the modelling of erosion could

also be a topic of research.

The current research consisted of becoming acquainted with the software and carrying out basic tests to

verify the outcomes. During the research it emerged that the shape of the particles determines whether the

expected behaviour of sand can be replicated. Also the relation between micro and macro properties, i.e. the

static friction of particle and the angle of internal friction, was investigated. Using a particle consisting of a

number of spheres with an irregular shape did give very good results. Passive earth pressure simulations

gave a very good match with the analytical solution, as did cutting tests in dry sand with a number of

cutting angles. Using a cutting angle of 90 degrees resulted in the occurrence of a wedge in front of the

blade with a wedge angle corresponding to literature.

Keywords:

  • Authors: Abdeli, M., Miedema, S.A., Schott, D.L., Alvarez Grima, M.
  • Year: 2010
  • Title: Discrete Element Method Modelling of Sand Cutting
  • Occasion: WODCON XIX Beijing
  • Issue: 2010
  • Pages: 21 pages
  • Type: Conference Paper
  • Publisher: WODA
  • {$string[350]} Download now


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