Task 4: DEM Modeling of Soil-Pile System Status Report

Task 4: DEM Modeling of Task 4: DEM Modeling of Soil-Pile SystemSoil-Pile System

Status ReportStatus Report

Claudia MedinaMourad Zeghal

RPI, February 15, 2005

ObjectiveObjective

DEM modeling of soil-pile system– Coupled Soil-Pile model– Flexible (Elastic) Pile

Soil-Pile SystemSoil-Pile System

Soil-Pile ModelSoil-Pile Model Soil: Discrete Element Method (DEM) Pile: FEM (Bernoulli-Euler beam theory) Algorithm:

DEM

for particles

fKu 1

Displacement for particles

Force acting on the pile

Forces acting on particles

Displacement for pile

FEM

for pile

Bernoulli-Euler Bernoulli-Euler beam theorybeam theory

Beam finite elements– 2 end nodes and 4 DOF– Neglects transverse shear deformations

2

2

1

1

v

v

eu

E, I

l

x, u

v 2

v 1

y, v 2

1

1 2

Element EquationElement Equation

2

22

3

4612

264612612

lsymml

lllll

lEIeK

eee fuK

l

lqle

6

6

12f

Global EquationGlobal Equation

1 GGGGGG fKufuK

[KG] =

K1

K2

K3

Kn

Assembly procedure for the beam with n elements

Model PropertiesModel PropertiesDEM model Prototype

g-level 50g 1gPile Radius, R 3 mm 15 cm Length, L 5 cm 2.5 m Young’s modulus, E 200 GPa 200 GPa Moment of inertia, I 0.0636 mm4 39.76 cm4

No elements 10Deposit Slope 5 (deg) 5 (deg) Particle radius, r 1 mm

DEM SimulationDEM Simulation

t = 0

DEM SimulationDEM Simulation

t = 0.05 sec

DEM SimulationDEM Simulation

t = 0.10 sec

DEM SimulationDEM Simulation

t = 0.15 sec

DEM SimulationDEM Simulation

t = 0.20 sec

DEM SimulationDEM Simulation

t = 0.25 sec

DEM SimulationDEM Simulation

t = 0.30 sec

DEM SimulationDEM Simulation

t = 0.35 sec

DEM SimulationDEM Simulation

t = 0.40 sec

DEM SimulationDEM Simulation

t = 0.45 sec

DEM SimulationDEM Simulation

t = 0.50 sec

Pile displacementPile displacement

Pile Displacement

0123456789

10

0 0.1 0.2 0.3 0.4 0.5

Time (s)

Nod

e di

spla

cem

ent (

cm)

N0 N1 N2 N3 N4 N5 N6 N7 N8 N9 N10

Pile displacementPile displacement

Pile Displacement

0123456789

10

0 2 4 6 8 10

Displacement (cm)

Nod

e

t = 0 s t = 0.05 s t = 0.10 s t = 0.15 s t = 0.20 s t = 0.25 st = 0.30 s t = 0.35 s t = 0.40 s t = 0.45 s t = 0.50 s

Thank youThank you