Abstract

This paper discusses the design and development of a new direct simple shear (DSS) apparatus for testing peat soils. The apparatus has been designed to test peat at low effective stresses, representative of its in situ condition and allow the deformation of the specimen to be monitored. This device uses particle image velocimetry (PIV) image analysis techniques to monitor the side of the peat specimen and provide an insight into the behavior of peat during shearing. A set of comparative tests on reconstituted clay have been conducted with another widely used DSS apparatus and has shown both to yield similar undrained strength ratios (suvc) for a range of stress levels. Application of the apparatus to peat soils is demonstrated by a set of tests on a high water content blanket bog peat. Analysis of these tests using the PIV technique reveals the complex shear strain and volumetric strain behavior of peat undergoing shearing. Identification of partial slippage of a specimen is also shown through these analyses.

References

1.
Airey
,
D. W.
,
1984
, “
Clays in Circular Simple Shear Apparatus
,” Ph.D. thesis,
University of Cambridge
.
2.
Airey
,
D. W.
, and
Wood
,
D. M.
,
1984
, “
Discussion on: Specimen Size Effect in Simple Shear Test
,”
J. Geotech. Engrg. Div.
 0093-6405, Vol.
110
, No.
3
, pp.
439
442
.
3.
Airey
,
D. W.
, and
Wood
,
D. M.
,
1987
, “
An Evaluation of Direct Simple Shear Tests on Clay
,”
Géotechnique
 0016-8505, Vol.
37
, No.
1
, pp.
25
35
.
4.
Airey
,
D. W.
,
Budhu
,
M.
, and
Wood
,
D. M.
,
1985
, “
Some Aspects of the Behaviour of Soils in Simple Shear
,”
Developments in Soil Mechanics and Foundation Engineering-2
,
Banerjee
,
P. K.
, and
Butterfield
,
R.
, Eds.,
Elsevier Applied Science
,
New York
, pp.
185
213
.
5.
Bjerrum
,
L.
, and
Landva
,
A. O.
,
1966
, “
Direct Simple-Shear Tests on a Norwegian Quick Clay
,”
Géotechnique
 0016-8505, Vol.
16
, No.
1
, pp.
1
20
.
6.
Boylan
,
N.
,
Jennings
,
P.
, and
Long
,
M.
,
2008
, “
Peat Slope Failure in Ireland
,”
Quarterly Journal of Engineering Geology and Hydrogeology
, Vol.
41
, No.
1
, pp.
93
108
.
7.
Budhu
,
M.
,
1979
, “
Simple Shear Deformation of Sands
,” Ph.D. thesis,
University of Cambridge
.
8.
Budhu
,
M.
,
1984
, “
Nonuniformities Imposed by Simple Shear Apparatus
,”
Can. Geotech. J.
 0008-3674, Vol.
21
, No.
1
, pp.
125
137
.
9.
Burland
,
J. B.
,
1990
, “
On the Compressibility and Shear Strength of Natural Clays
,”
Géotechnique
 0016-8505, Vol.
40
, No.
3
, pp.
329
378
.
10.
DeGroot
,
D. J.
,
Germaine
,
J. T.
, and
Gedney
,
R.
,
1991
, “
An Automated Electropneumatic Control System for Direct Simple Shear Testing
,”
Geotech. Test. J.
 0149-6115, Vol.
14
, No.
4
, pp.
339
348
.
11.
Den Haan
,
E. J.
, and
Kruse
,
G. A. M.
,
2007
, “
Characterization and Engineering Properties of Dutch Peats
,” Proceedings of Characterization and Engineering Properties of Natural Soils, Singapore, Vol.
3
, pp.
2101
2133
.
12.
Dyvik
,
R.
,
Berre
,
T.
,
Lacasse
,
S.
, and
Raadim
,
B.
,
1987
, “
Comparison of Truly Undrained and Constant Volume Direct Simple Shear Tests
,”
Géotechnique
 0016-8505, Vol.
37
, No.
1
, pp.
3
10
.
13.
Farrell
,
E. R.
, and
Hebib
,
S.
,
1998
, “
The Determination of the Geotechnical Parameters of Organic Soils
,” Proceedings of International Symposium on Problematic Soils, IS-TOHOKU 98, Sendai, Japan, pp.
33
36
.
14.
Helenelund
,
K. V.
,
1967
, “
Vane Tests and Tension Tests on Fibrous Peats
,” Proceedings Geotech. Conference on Shear Strength Properties of Natural Soils and Rocks, Oslo, Vol.
1
, pp.
199
203
.
15.
Hobbs
,
N. B.
,
1986
, “
Mire Morphology and the Properties and Behaviour of Some British and Foreign Peats
,”
Q. J. Eng. Geol.
 0481-2085, Vol.
19
, pp.
7
80
.
16.
Kjellman
,
W.
,
1951
, “
Testing the Shear Strength of Clay in Sweden
,”
Géotechnique
 0016-8505, Vol.
2
, No.
3
, pp.
225
232
.
17.
Ladd
,
C. C.
,
1991
, “
Stability Evaluation During Staged Construction
,”
J. Geotech. Engrg. Div.
 0093-6405, Vol.
117
, No.
4
, pp.
540
615
.
18.
Landva
,
A. O.
,
1980
, “
Vane Testing in Peat
,”
Can. Geotech. J.
 0008-3674, Vol.
17
, No.
1
, pp.
1
19
.
19.
Prevost
,
J. H.
, and
Høeg
,
K.
,
1976
, “
Reanalysis of Simple Shear Soil Testing
,”
Can. Geotech. J.
 0008-3674, Vol.
13
, No.
4
, pp.
418
429
.
20.
Roscoe
,
K. H.
,
1953
, “
An Apparatus for the Application of Simple Shear to Soil Samples
,” Proceedings of the 3rd International Conference on Soil Mechanics and Foundation Engineering, London, Vol.
1
, pp.
186
191
.
21.
von Post
,
L.
, and
Granlund
,
E.
,
1926
, “
Peat Resources in Southern Sweden
,”
Sveriges geologiska undersökning, Yearbook
, Vol.
335
, No.
19.2
Series C, pp.
1
127
.
22.
White
,
D. J.
, and
Take
,
W. A.
,
2005
, “
Discussion on: Application of Particle Image Velocimetry (PIV) in Centrifuge Testing of Uniform Clay
,”
Int. J. Phys. Modell. Geotech.
 1346-213X, Vol.
5
, No.
4
, pp.
27
31
.
23.
White
,
D. J.
,
Take
,
W. A.
, and
Bolton
,
M. D.
,
2003
, “
Soil Deformation Measurement Using Particle Image Velocimetry (PIV) and Photogrammetry
,”
Géotechnique
 0016-8505 https://doi.org/10.1680/geot.53.7.619.37383, Vol.
53
, No.
7
, pp.
619
631
.
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