Code_Aster ®
Version
5.0
Titrate:
SSNV136 - Triaxial Essai drained with model CJS (level 2)
Date:
05/02/02
Author (S):
C. CHAVANT, pH. Key AUBERT
:
V6.04.136-A Page:
1/6

Organization (S): EDF/AMA, CNEPE
Handbook of Validation
V6.04 booklet: Nonlinear statics of the voluminal structures
Document: V6.04.136
SSNV136 - Triaxial Essai drained with model CJS
(level 2)

Summary

This test makes it possible to validate level 2 of model CJS. It is about a triaxial compression test in drained condition.
calculations are carried out only on the solid part of the ground, without hydraulic coupling. The level of
containment is of 100 kPa.
By reason of symmetry, one is interested only in the eighth of a sample 3D subjected to a triaxial compression test.
It is about a test of nonregression. Nevertheless, results obtained with Code_Aster for model CJS2
are compared with those obtained with a private version of software FLAC - 2D.
Handbook of Validation
V6.04 booklet: Nonlinear statics of the voluminal structures
HT-66/02/001/A

Code_Aster ®
Version
5.0
Titrate:
SSNV136 - Triaxial Essai drained with model CJS (level 2)
Date:
05/02/02
Author (S):
C. CHAVANT, pH. Key AUBERT
:
V6.04.136-A Page:
2/6

1
Problem of reference

1.1 Geometry
Z
E
height:
H = 1 m
width:
L
= 1 m
thickness:
E = 1 m
C
H
With
B
y
X
L


Co-ordinates of the points (in meters):

With
B
C
X 0. 0.
0.5
y 0. 1.
0.5
Z 0. 0.
0.5

1.2
Material property

E = 35,6616541 103 kPa
= 0,15037594

Parameters CJS2:
= - 0,55
= 0,82
Rm = 0,289
Rc = 0,265
N = 0,6

K p
O = 25,5 103 kPa
With = 0.25 kPa
Pa = - 100 kPa

1.3
Initial conditions, boundary conditions, and loading

Phase 1:
One brings the sample in a homogeneous state: 0 = 0 = 0
xx
yy
zz, by imposing the pressure of
containment corresponding on the front, side straight line and higher faces. Displacements are
blocked on the faces postpones (ux = 0), side left (uy = 0) and lower (uz = 0).

Phase 2:
One maintains displacements blocked on the faces postpones (ux = 0), side left (uy = 0) and
lower (uz = 0), as well as the confining pressure on the front faces and side straight line. One
apply a displacement imposed to the higher face: U (T)
Z
, in order to obtain a deformation
zz = - 20% (counted starting from the beginning of phase 2).
Handbook of Validation
V6.04 booklet: Nonlinear statics of the voluminal structures
HT-66/02/001/A

Code_Aster ®
Version
5.0
Titrate:
SSNV136 - Triaxial Essai drained with model CJS (level 2)
Date:
05/02/02
Author (S):
C. CHAVANT, pH. Key AUBERT
:
V6.04.136-A Page:
3/6

2
Reference solution

2.1
Method of calculation used for the reference solution

The results obtained with the software a private version of the software Flac-2D are used as reference.

2.2
Results of reference

Constraints xx, yy and zz at points A, B and C.

2.3
Uncertainty on the solution

Uncertainty related to the software Flac-2D.

2.4 Bibliography

[1]
Board, “FLAC (Fast Lagrangian Analysis off Continua) Version 2.20. U.S. NRC”,
NUREG/CR-5430, October 1989.
[2]
“Flac Fast Lagrangian Analysis off Continua. Theory and Background. ” Itasca Consulting
Group.

Handbook of Validation
V6.04 booklet: Nonlinear statics of the voluminal structures
HT-66/02/001/A

Code_Aster ®
Version
5.0
Titrate:
SSNV136 - Triaxial Essai drained with model CJS (level 2)
Date:
05/02/02
Author (S):
C. CHAVANT, pH. Key AUBERT
:
V6.04.136-A Page:
4/6

3 Modeling
With

3.1
Characteristics of modeling

3D:
Z
B
y
X


Cutting: 2 in height, in width and thickness.

Loading of phase 1:
Confining pressure: 0 = 0 = 0
xx
yy
zz: successively ­ 100 kPa, ­ 200 kPa and ­ 400 kPa.
Level 2 of model CJS

3.2
Characteristic of the grid

A number of nodes: 27
A number of meshs and types: 8 HEXA8 and 24 QUA4

3.3 Functionalities
tested

Commands




DEFI_MATERIAU CJS



STAT_NON_LINE COMP_INCR
RELATION
“CJS”


Handbook of Validation
V6.04 booklet: Nonlinear statics of the voluminal structures
HT-66/02/001/A

Code_Aster ®
Version
5.0
Titrate:
SSNV136 - Triaxial Essai drained with model CJS (level 2)
Date:
05/02/02
Author (S):
C. CHAVANT, pH. Key AUBERT
:
V6.04.136-A Page:
5/6

4
Results of modeling A

4.1 Values
tested

For 0 = 0 = 0
xx
yy
zz: ­ 100 kPa

Localization Numéro deformation
constraint
Reference
Aster %
difference
of command
axial
(kPa)
zz (%)
Not A, B and C

­ 0.8%

xx
­ 100.0
­ 100.013 <
0.05

­ 20.0
%
xx
­ 100.0 ­ 100.020
< 0.05


­ 0.8%
yy
­ 100.0
­ 100.013 <
0.05

­ 20.0
%
yy
­ 100.0 ­ 100.020
< 0.05


­ 0.8%
zz
­ 286.8
­ 286.838 <
0.05

­ 1.6
%
zz
­ 332.9
­ 332.965 <
0.05

­ 3.2
%
zz
­ 350.8
­ 350.894 <
0.05

­ 7.2
%
zz
­ 356.1
­ 356.144 <
0.05

­ 20.0
%
zz
­ 358.8
­ 358.849 <
0.05

4.2 Parameters
of execution

Version:
5.02.16


Machine:
SGI-ORIGIN 2000-R12000


Obstruction memory: 128 MO
Time CPU To use: 172s

Handbook of Validation
V6.04 booklet: Nonlinear statics of the voluminal structures
HT-66/02/001/A

Code_Aster ®
Version
5.0
Titrate:
SSNV136 - Triaxial Essai drained with model CJS (level 2)
Date:
05/02/02
Author (S):
C. CHAVANT, pH. Key AUBERT
:
V6.04.136-A Page:
6/6

5
Summary of the results

The values of the constraints obtained with Aster coincide with those of software FLAC with one
lower deviation than 0,05%.
Handbook of Validation
V6.04 booklet: Nonlinear statics of the voluminal structures
HT-66/02/001/A

Outline document