2928
Proceedings of the 18
th
International Conference on Soil Mechanics and Geotechnical Engineering, Paris 2013
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
1 2 3 4 5 6 7 8 9 1011121314151617181920
S
u
/σ'
v
OCR
CP601
CP604
CP606
CP609
SHANSEP
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
0
200
400
600
800
1,000
1,200
0
500
1,000
1,500
2,000
2,500
3,000
Fill Thickness (m)
Settlement (mm)
Monitoring Point - MP1
Monitoring Point - MP2
Monitoring Point - MP3
Prediction Primary Settlement
Fill Thickness
Time (days)
Figure 6. Interpretation of CPTu data based on SHANSEP
normalization procedure.
Figure 8. Settlement prediction at the centerline of motorway
embankment.
12 FRAMEWORK OF SETTLEMENT ANALYSIS
14 CONCLUSIONS
Previous examinations of the one-dimensional response of a
large number of clay soils (Skempton and Northey 1952),
suggest the possibility to develop a correlation between the soil
sensitivity and liquidity index. The oedometric results of virgin
AH soils are interpreted in Figure 7 using LI as a normalizing
parameter.
The paper presents some of the results collected as part of an
extensive geotechnical investigation carried out into the sub-
surface conditions of the Causeway Section of SH16. The main
findings of the paper are summarized below:
The one-dimensional compression curves are observed to
“bundle together” in the stress range greater than pre-
consolidation stress,
’
p
. Such normalization procedure may be
modeled by a non-linear relationship expressed as follows:
1. The undrained shear strength ofvirginAH soils manifests a
linear increase with depth.
2. The compressibility of virginAH soil in one-dimensional
testing displays non-linear characteristics when stresses
exceed the pre-consolidation pressure.
3. The assessment of undrained shear strength of virginAH
soil is not readily predicted by methods such as SHANSEP.
2
'
21.0
90
LI
v
(3)
The predictive capability of equation (3) is illustrated in
Figure7 by the dotted line.
4. The one-dimensional response of virginAH soil is found to
uniquely relate LIand
’
v
. The predictive capability of a
proposed relationship is demonstrated by numerical
simulations of settlement monitored during the construction
and post-construction phase of SH16 motorway
embankment.
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
10
100
1,000
BH22A: RL=‐0.9m
BH31C: RL=‐3.2m
Newland(1955): RL=‐ 3.9m
DH423: RL=‐6.3m
BH31B: RL=‐7.7m
Remould Sample
Prediction
Liquidity Index ‐ LI
Vertical Stress ‐
'
v
(kPa)
15 REFERENCES
Been K. and Jefferies M.G. 1985. A state parameter for sands,
Géotechnique
, 35 (2), 99-112.
Bjerrum L. 1973. Problems of soil mechanics and construction on soft
clays,
Proceedings of 8
th
International Conference on Soil
Mechanics and Foundation Engineering
, Moscow, 3, 111-159.
Bobei D.C. Lo S. R. Wanatowski D. Gnanendran C. T. and Rahman, M.
M. 2009. A modified state parameter for characterizing static
liquefaction of sand with fines,
Canadian Geotechnical Journal
, 46
(3), 281-295.
Figure 7. Prediction of non-linear oedometer compression curves.
Burland J.B. 1990. On the compressibility and shear strength of virgin
clays,
Géotechnique
, 40(3), 329-378.
13 SETTLEMENT PREDICTION
The embankment construction progressed gradually on the
surface of soft marine muds to form a series of containment
cells, to be later in-filled with granular (sand and shell) and
cohesive clay material.
Ladd C.C. and Foot R. 1974. New design procedure for stability of soft
clays,
Journal of Geotechnical Engineering Division
, ASCE,
100(7), 767-787.
An in-house spreadsheet was developed to incorporate the
non-linear relationship (3) to describe the compression response
of the virginAH soil.The main features embedded into the
spreadsheet include: (a) multi-layered soil configuration; (b)
vertical stress increase with depth calculated based on 2D
embankment geometry; (c) reduction in
’
v
due to submergence
of fill embankment below the ground water table; (d)
calculation of primary consolidation using Terzaghi’s 1-D
consolidation theory; and (e) calculation of creep settlement.
Lunne T. Berre T. and Strandvik S. 1997. Sample disturbance on soft
low plastic Norwegian clay,
Proceeding of the International
Symposium on Recent Developments in Soil and Pavement
Mechanics
, Rio de Janeiro, Brazil, 25-27.
Roscoe K.H Schofield A.N. and Wroth C.P. 1958. On yielding of soils,
Géotechnique
, 8, 22 - 53.
Rosenqvist I. Th. (1953) - Considerations of the sensitivity of
Norwegian quick clays,
Géotechnique
, 3(5), 195-200.
Skempton A.W. and Northey R.D. 1952. The sensitivity of clays,
Géotechnique
, 3, 30-53.
Taylor D.W. 1942. Fundamentals of Soil Mechanics, New York, Wiley
Publishers, 229-239.
The prediction is found to simulate considerably well the
magnitude and rate of settlement development with time as
shown in Figure 8.
Wroth, C.P. and Wood, D. M. 1978. The correlation of index properties
with some basic engineering properties of soils,
Canadian
Geotechnical Journal
, 15(2), 137-145.
