542
Proceedings of the 18
th
International Conference on Soil Mechanics and Geotechnical Engineering, Paris 2013
Fr = [f
s
/(q
t
-
vo
)] 100, %
1
10
k
OCR
= OCR/[(q
t
-
vo
)/
'
vo
]
1.25
0.0
0.2
0.4
0.6
0.8
1.0
Idku
Metobus
Dammietta 3
Dammietta 4
PortSaid 2
El-Gamil
Dammietta 2
Average k
OCR
= 0.23
2
3
4 5 6 7 8 9
Robertson (2012)
Equ. (10)
Ladd & DeGroot (2003)
Robertson (2009)
Figure (6) Empirical constant k
OCR
for the sites in the study
(q
t
-
vo
)/p
a
0
2
4
6
8 10 12 14
o
= M
o
/(q
t
-
vo
)
0
5
10
15
20
25
30
Idku
Metobus
Dammietta3
Dammietta4
PortSaid2
El-Gamil
Dammietta2
Average
o = 3.5
Range from
literature
5.2. Constrained Modulus
Review of the available correlations between M and cone
results for cohesive soil was carried out by Lunne et al. (1997),
Mayne (2001), Pant (2007), and Robertson (2009). Attempts to
correlate M of cohesive soils to cone results have started since
mid sixties of the last century (Sanglerat, 1972). The following
expression shows the general form of the empirical correlation:
M
Subscript
=
Subscript
[q
Parameter
]
(11)
The subscript in Equ (11) could be nothing, i, np, n, or o as
in Equs (1 to 5). The empirical constant
as well as the cone
parameter, q
Parameter
, used in Equ (11) as reported in literature is
summarized in Table (2). According to the table,
o
is in the
range of 1 to 14. Sanglerat (1972) showed that
o
is inversely
dependent on q
c
. Robertson (2009) suggested that
o
is directly
related to (q
t
-
vo
)/
’
vo
with an upper limit of 14. The empirical
constant
o
is calculated for the data in this study and is plotted
versus (q
t
-
vo
)/p
a
in Figure (7), where p
a
is a reference pressure
of 100 kPa.. Ignoring some scatter, the calculated
o
values are
in the range of 1 to 8 with an average of 3.5, which is consistent
with the existing correlations in the literature. Sources of scatter
in Figure (7) include but not limited to; sample disturbance with
its influence on the measured compressibility and natural
variation between the location of borehole from which the
samples were extracted and that of the CPTU testing.
Table (2) Summary of components of empirical Equ. (11) in literature
Reference
Subscript
Range
q
Parameter
Comment
Bachelier and Parez (1965)
o
2.3-7.7
q
c
Flanders Clay
Sanglerat (1972)
o
1-8 *
q
c
France & Spain Clays
Jones & Rust (1995)
o
2.2-3.3
q
c
South African Clays
Pants (2007)
np
3.1
q
t
Louisiana Clay
np
3.27
q
t
-
vo
Louisiana Clay
Kulhawy & Mayne (1990)
8.25
q
t
-
vo
Senneset et al. (1989)
i
5-15
q
t
-
vo
Glava Clay
np
8
q
t
-
vo
Glava Clay
Abdelrahman et al. (2005)
o
1.25
q
t
-
vo
Port Said Clay
Mayne (2009)
5
q
t
-
vo
Vanilla Clays
Robertson (2009)
o
**
q
t
-
vo
* Dependent on type of soil and on q
c
values
** For Clays (Ic > 2.2)
o
= (q
t
-
vo
)/
’
vo
o
≤ 14
Figure (7) Empirical constant
o
for the sites in the study
6 SUMMARY AND CONCLUSIONS
1) The results of geotechnical investigations in seven sites in
the Nile Delta clays were used in this paper.
2) The compressibility parameters; OCR, C
c
and C
r
, and M
o
,
were calculated from EOP e-log
’
v
curves of total 125
consolidation tests carried out on “undisturbed” samples. The
SQD of the majority of the samples was B to C.
3) The compressibility parameters of each test were paired
with results from neighboring or adjacent piezocone test that
were recorded at the same depths of the samples. Such
pairing allowed for comprehensive review of the existing
empirical correlations to predict compressibility parameters
from in-situ piezocone results.
4) The OCR of the Nile Delta clays can be best predicted
using Equs. (8) and (9) using average k of 0.32 and average
k
OCR
of 0.23. Figs (5) & (6) suggest that k and k
OCR
have the
general tendency to slightly increase with friction ratio, F
r
.
5) The M
o
can be best predicted using Equ. (11) with average
value of
o
of 3.5. Settlement analysis can then be carried out
using M
i
and M
n
that can be calculated using Equs (6) and
(7).
7 REFERENCES
Abdelrahman M., Ezzeldine O.and Salem M. 2005. The Use of Piezocone in
Characterization of Cohesive Soil West of Port Said – Egypt,
Proc. of 5
th
Int.
Geot. Eng. Conf.,
– Cairo University – Egypt, pp. 201-219.
Bachelier M. and Parez L.1965. Cont ribution a letude de la compress ibilite’ des sols a
l’aide du penetrometer a cone,
Proc. 6
th
Int. Conf. Soil Mech. Found. Eng.
,
Montreal, 2, 3-10.
Becker, D. E. 2010. Testing in Geotechnical Design,
Geot. Eng. Jour. of the
SEAGS & AGSSEA
, Vol. 41, No. 1, pp. 1-12.
Campanella, R.G. and Robertson P. K. 1988. Current status of piezocone test,
Proc. of Int. Symp. on Penetration Testing
, Orlando, USA, Vol. 1, pp. 1-24.
Chen B. and Mayne P.W. 1996. Statistical relationships between piezocone
measurements & stress history of clays,
Can. Geot. Jour.
33(3), pp. 488–498.
Jamiolkowski M., Ladd C.C., Germaine J.T., and Lancelotta R. 1985. New
Development in Field and Laboratory Testing of Soils,
Proc. of the 11
th
Int.
Conf. Soil Mech. and Found. Eng.,
San Francisco, 1, pp. 57-153.
Hamza M., Shahien M. and Ibrahim M. 2003. Ground characterization of Soft
Deposits in Western Nile Delta,
Proc. 13
th
Reg. African Conf. Soil Mech.
Geot. Eng.
, Morocco.
Hamza M., Shahien M. and Ibrahim M. 2005. Characterization and undrained
shear strength of Nile delta soft deposits using piezocone,
Proc. 16
th
Int.
Conf. on Soil Mech. and Geot. Eng.
, Osaka, Japan
Hamza M. and Shahien M. 2009. Effective stress shear strength parameters from
piezocone,
Proc.17
th
Int. Conf.Soil Mech. and Geot. Eng.
, Alexandria, Egypt.
Hight D.W. Hamza M.M. and ElSayed A.S. 2000. Engineering characterization of
the Nile Delta clays,
Proc. of IS
Yokohama 2000.
Janbu N. 1963. Soil compressibility as determined by oedometer and triaxial tests,
Proc. European Conf. Soil Mech. and Found. Eng.
Wiesbaden, 1, 19–25.
Jones G.A. and Rust E. 1995. Piezocone settlement prediction parameters for
embankments on alluvium, Proc.
Int. Symp. Cone Penetration Testing
,
Linköping, Sweden, 2, 501–8.
Ladd, C. C. and DeGroot D. J. 2003. Recommended Practice for Soft Ground Site
Characterization,
Proc. 12th Panamerican Conf. Soil Mech. and Geot. Eng.,
Cambridge, USA
Larson, R., and Mulabdic, M. 1991.
Piezocone tests in clays
. Swedish
Geotechnical Institute report no. 42, Linkoping, 240p.
Lefebvre, G. and Poulin C. 1979. A new method of sampling in sensitive clay ,
Canadian Geot. Journal
, Vol. 16, pp. 226–233.
Leroueil S., Demers D., La Rochelle P., Martel G. and Virely D. 1995. Practical
use of the piezocone in Eastern Canada clays ,
Proc. Int. Symp. on Cone
Penetration Testing,
Linköping, Sweden, 2, 515–522.
Lunne T., Robertson P.K., and Powell J.J.M. 1997.
Cone Penetration Testing in
Geotechnical Engineering Practice
. p. 312.
Mayne, P.W. 1991. Determination of OCR in clays by piezocone tests using cavity
expansion and critical state concepts.
Soils and Foundations
31 (1): 65-76.
Mayne P. W. 2001. Stress-strain-strength-flow parameters from enhanced in-situ
tests, Proc. Int. Conf. on In-Situ Measurement of Soil Properties & Case
Histories, Bali, Indonesia, pp. 27-48.
Mayne P. W., Coop M. R., Springman S. M., Huang A. and Zornberg J. G. 2009.
Geomaterial behavior and testing, State of the Art Lecture,
Proc. 17th Int.
Conf. on Soil Mech. and Geot. Eng.
Alexandria, Egypt, Vol. 4, pp. 1-96.
Mayne P.W., Holtz R.D. 1988. Profiling stress history from piezocone soundings,
Soils and Foundations
, Vol. 28(1), pp. 16–28.
Mesri G. 2001. Undrained shear strength of soft clays from push cone penetration
test , Geotechnique 51, No. 2, pp. 167–168.
Pant R. R. 2007.
Evaluation of Consolidation Parameters of Cohesive Soils Using
PCPT Method
. MSc Thesis, Louisiana State University. USA
Powell, J. J. M. and Lunne T. 2005. Use Of Cptu Data In Clays/Fine Grained
Soils,
Studia Geotechnica et Mechanica
, Vol. XXVII, No. 3–4, pp. 29-66.
Robertson, P. K. 2009. Interpretation of cone penetration tests – a unified
approach,
Canadian Geotechnical Journal
, Vol. 46, pp. 1337-1355.
Robertson P.K. 2012. Interpretation of in-situ tests – some insights,
Proc. 4th Int.
Conf. Geot. & Geoph. Site Characterization
, ISC’4, Brazil, 1, pp 1-22.
Sanglerat G. 1972.
The penetrometer and soil exploration
, Elsevier, 464 pp.
Senneset K., Sandven R. and Janbu N. 1989. The evaluation of soil parameters
from piezocone tests,
Transportation Research Record
, No. 1235, 24–37.
Terzaghi K., Peck R.B. and Mesri G. 1996.
Soil Mechanics in Engineering
Practice
, 3rd Ed. John Wiley and Sons, Inc., p. 549.
