Abstract

This paper describes a prototype device for ultra-small strain triaxial stiffness measurement, using laser-optic interferometry, and based upon the Fabry-Perot principle. The results of a test on an intact specimen of weak rock are presented, and comparisons made between measurements using this device and a submersible LVDT system. The displacement resolution of the interferometer was 0.0006 μm and the strain resolution 8 × 10−7%. It is shown that the measurement uncertainty of the instrument was low compared with the magnitude of the displacements measured and in addition it was sufficiently accurate to detect the linear stress-strain behavior of a weak rock.

Issue Section:
Research Papers
Keywords:
triaxial test, small strain stiffness, local strain instrumentation, laser interferometry

References

1.
Baldi
,
G.
,
Hight
,
D. W.
, and
Thomas
,
G. E.
,
1988
, “
A Re-Evaluation of Conventional Triaxial Test Methods
,”
Advanced Triaxial Testing of Soil and Rock
, ASTM STP 977,
ASTM International
,
West Conshohocken, PA
, pp.
219
-
263
.
2.
Born
,
M.
 and
Wolf
,
E.
,
1964
,
Principles of Optics. Electromagnetic Theory of Propagation, Interference and Diffraction of Light
, 3rd ed.,
Pergamon Press
,
London
.
3.
Brown
,
S. F.
 and
Snaith
,
M. S.
,
1974
, “
The Measurement of Recoverable and Irrecoverable Deformations in the Repeated Load Triaxial Test
,”
Géotechnique
, Vol.
24
, No.
2
, pp.
255
-
259
.
Google Scholar
Crossref
Search ADS
 
4.
Burland
,
J. B.
 and
Symes
,
M.
,
1982
, “
A Simple Axial Displacement Gauge for Use in the Triaxial Apparatus
,”
Géotechnique
, Vol.
32
, No.
1
, pp.
62
-
65
.
Google Scholar
Crossref
Search ADS
 
5.
Clayton
,
C. R. I.
 and
Heymann
,
G.
,
2001
, “
The Stiffness of Geomaterials at Very Small Strains
,”
Géotechnique
, Vol.
51
, No.
3
, pp.
245
-
256
.
Google Scholar
Crossref
Search ADS
 
6.
Clayton
,
C. R. I.
 and
Khatrush
,
S. A.
,
1986
, “
A New Device for Measuring Local Axial Strains on Triaxial Specimens
,”
Géotechnique
, Vol.
36
, No.
4
, pp.
593
-
597
.
Google Scholar
Crossref
Search ADS
 
7.
Clayton
,
C. R. I.
,
Khatrush
,
S. A.
,
Bica
,
A. V. D.
, and
Siddique
,
A.
,
1989
, “
The Use of Hall Effect Semiconductors in Geotechnical Instrumentation
,”
Geotechnical Testing Journal
 0149-6115, Vol.
12
,
03
1989
, pp.
69
-
76
.
8.
Cuccovillo
,
T.
,
1995
,
Shear Behaviour and Stiffness of Naturally Cemented Sands
,” PhD thesis,
City University
, London.
9.
Cuccovillo
,
T.
 and
Coop
,
M. R.
,
1997
, “
The Measurement of Local Axial Strains in Triaxial Testing Using LVDTs
,”
Géotechnique
, Vol.
47
, No.
1
, pp.
167
-
171
.
Google Scholar
Crossref
Search ADS
 
10.
Da Re
,
G.
,
Santagata
,
M. C.
, and
Germaine
,
J. T.
,
2001
, “
LVDT Based System for the Measurement of the Prefailure Behavior of Geomaterials
,”
Geotechnical Testing Journal
 0149-6115, Vol.
24
, No.
3
, pp.
288
-
298
.
11.
Dutta
,
N. K.
,
1987
, “
Optical Sources for Lightwave Systems Applications
,”
Optical Fiber Transmission
,
Basch
 
E. E.
, Ed.,
H. W. Sams and Company
.
12.
Eden
,
B.
,
1966
,
Metrologia
 0026-1394 https://doi.org/10.1088/0026-1394/2/2/002, Vol.
2
, pp.
71
-
80
.
Crossref
Search ADS
 
13.
Goto
,
S.
,
Tatsuoka
,
F.
,
Shibuya
,
S.
,
Kim
,
Y.
, and
Sato
,
T.
,
1991
, “
A Simple Gauge for Local Small Strain Measurements in the Laboratory
,”
Soils and Foundations
, Vol.
31
, No.
1
, pp.
169
-
180
.
Google Scholar
Crossref
Search ADS
 
14.
Heymann
,
G.
,
1998
, “
The Stiffness of Soils and Weak Rocks at Very Small Strains
,” PhD Thesis,
University of Surrey
, UK.
15.
Heymann
,
G.
,
Clayton
,
C. R. I.
, and
Reed
,
G. T.
,
1997
, “
Laser Interferometry to Evaluate the Performance of Local Displacement Transducers
,”
Géotechnique
, Vol.
47
, No.
3
, pp.
399
-
405
.
Google Scholar
Crossref
Search ADS
 
16.
Hird
,
C. C.
 and
Yung
,
P. C. Y.
,
1989
, “
The Use of Proximity Transducers for Local Strain Measurements in Triaxial Tests
,”
Geotechnical Testing Journal
 0149-6115, Vol.
12
, No.
4
, pp.
292
-
296
.
17.
Jardine
,
R. J.
,
Potts
,
D. M.
,
Fourie
,
A. B.
, and
Burland
,
J. B.
,
1986
, “
Studies of the Influence of Non-Linear Characteristics in Soil-Structure Interaction
,”
Géotechnique
, Vol.
36
, No.
3
, pp.
377
-
396
.
Google Scholar
Crossref
Search ADS
 
18.
Jardine
,
R. J.
,
Potts
,
D. M.
,
St. John
,
H. D.
, and
Hight
,
D. W.
,
1991
, “
Some Practical Applications of a Non-Linear Ground Model
,”
Proceedings, 10th European Conference of Soil Mechanics and Foundation Engineering
,
Florence
, Vol.
1
, pp.
223
-
228
.
19.
Jardine
,
R. J.
,
Symes
,
M. J.
, and
Burland
,
J. B.
,
1984
,
The Measurement of Soil Stiffness in the Triaxial Apparatus
,”
Géotechnique
, Vol.
34
, No.
3
, pp.
323
-
340
.
Google Scholar
Crossref
Search ADS
 
20.
Mair
,
R. J.
,
1993
, “
Developments in Geotechnical Engineering Research: Application to Tunnels and Deep Excavation, Unwin Memorial Lecture
,”
Proceedings of the Institution of Civil Engineers, Civil Engineering
, Vol.
93
, pp.
27
-
41
.
21.
Pedrotti
,
F. L.
 and
Pedrotti
,
L. S.
,
1993
,
Introduction to Optics
, 2nd ed.,
Prentice-Hall
.
22.
Tatsuoka
,
F.
,
1988
, “
Some Recent Developments in Triaxial Testing Systems for Cohesionless Soils
,”
Advanced Triaxial Testing of Soil and Rock
, ASTM STP 977,
ASTM International
,
West Conshohocken, PA
, pp.
7
-
67
.
This content is only available via PDF.
All rights reserved. This material may not be reproduced or copied, in whole or in part, in any printed, mechanical, electronic, film, or other distribution and storage media, without the written consent of ASTM International.
You do not currently have access to this content.