Failure Phenomenon Simulation Failure Phenomenon Simulation by MPS-DEMby MPS-DEM

Geotechnical Structure

Elastic behavior: MPS

Failure: DEM

Strength Parameters

Tensile Strength for failure

Maximum Shear Strength (not failure) 　

2

ijnijijc tanmax

tnij c

ct

cij

ij

nij

Shear Stress

Normal Stress

Tensile Compression

Initial

1st parameter

ij

ct

cij New contact

2nd parameter

Coh_lij

Compression TestHomogenous Compressive Condition

Compression TestHomogenous Compressive Condition

Step-2 Compression1: 　 constant x-stress

2: 　 constant y-stress

3: 　 enforced y-displacement, x-fix

4: 　 x,y fix

Step-1 Confining Stress1: 　 x-stress, 2: 　 x-stress

3: 　 y-stress, 4: 　 y-fix

Confining Stress

　25 kN/m2

4

3

1 2

10m

20m

4

3

1 2

x

y

3

Compression TestCompression Test

Type-2 formulation

4

Number of disconnected particles 0, 1, 2, 3, 4 more than 5

magnification ratio 5.0

• Failed particles appear on conjugate 45 degree line regularly

• Nonlinearity can not be observed in strain-stress relation, etc.,

It is known that the regular gird (lattice) alignment affect the failure behavior

JUMP

Macro Strain and StressStrain=disp. at top/lengthStress=force at top/wedth

Compression TestCompression TestRandom Model 1

Seed of random number 111113

5

Number of disconnected particle 0, 1, 2, 　 　 more than 3

magnification ratio 5.0

Jump Jump

6

Number of disconnected particle 0, 1, 2, 　 　 more than 3

Seed of random number 111112 6

Compression TestCompression TestRandom Model 2

magnification ratio 5.0

Compression TestCompression TestComparison of lattice model and

random model

7

Output Memo

8

Case 1 Big ModelConfining Pressure=50

1.5-3.0 seconds

Interaction condition

InteractionBlue :initial, orange:weakRed: Dem, green:mps

2.0秒間ではev2がメモリ不足Uper, lower layer=0.4m, Seed of random number=1111112

Acceleration (H)

Dev

iato

nic

Str

ess

Axial Strain