Invitation to International Prediction Event
on the Behaviour of
Bored, CFA and Driven Piles in ISC’2 experimental site - 2003
Jaime Santos, Coordinator of the experimental site
A. Viana da Fonseca, President of ISC’2
1. INTRODUCTION
The Conference ISC’2 (International Site Characterization) will be held in 2004 at the Faculty of
Engineering, University of Porto (FEUP), Portugal. The Conference addresses the use and
benefits of geotechnical site characterization, in particular field tests for the exploration of the
subsurface environment. An experimental site with very extensive site characterization is being
undertaken, including a large variety of in-situ tests and also pile load tests (for more details
about the conference please visit the web site http//www.fe.up.pt/isc-2).
The FEUP and IST (Instituto Superior Técnico) is pleased to organize an International Prediction
Event on the Behaviour of Bored, CFA and Driven Piles in ISC’2 experimental site - 2003.
2. BACKGROUND
In the north-western region of Portugal residual soils from granite are dominant. The thickness of
these regional saprolitic soils may some times attain more than 20m, with more common values
of 5 to 10m. Due to their specific genesis such soils present complex characteristics, which are a
consequence, on the one hand, of their overall variability and heterogeneity and, on the other
hand, of the spatial arrangement and distribution of the particles and pore spaces. Coarse and
resistant quartz grains are bonded by fragile clayey plagioclase bridges, resulting in a fabric with
medium to high porosity. The feldspars are subjected to intense weathering processes, typical of
high average annual precipitation and well-drained ground profiles. The mechanical and
hydraulic behaviour of these soils is often quite distinct from sedimentary soils with similar
densities and grain size distributions.
The current design practice of bored and driven piles in residual weathered formations is merely
semi-empirical and based on bearing capacity analysis (in general, without deformations
analysis). Fully instrumented pile load tests are very much informative for the elaboration of
specific correlations between load-deformation behaviour and in situ tests results (and also
fundamental soil mechanics parameters obtained from precise laboratory tests), for establishing
well-based design criteria. The possibility of integrating very wide information in a typical
granite residual soil profile will enable an innovative study on this subject.
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3. OUTLINE DESCRIPTION OF LOAD TESTS PROGRAM
3.1 Soil Characterization
In the experimental site the thickness of the residual saprolitic soils is near 20m. Several in-situ
testing techniques (Seismic: CH, DH, SASW, CSWS; Penetration tests: SPT & CPT; Pressuredilatometer tests: PMT, SBPT, DMT; and Load tests: PLT and a full-scale footing testing) have
been used in order to have a very sound knowledge of the mechanical characteristics of this soil.
High quality undisturbed block samples were recovered and an extensive laboratory testing
program was carried out, including isotropic and oedometric consolidation tests, as well as CID
and CK0D triaxial tests using local strain measuring devices and bender-extender elements.
Several papers (see Section 5: References) have presented and discussed the results obtained,
giving emphasis to the interpretation of constitutive behaviour differences in stress-strain levels
lower and higher than the yield stresses related to saprolitic soils with weak relic structures. This
research is on going with the present campaign. Some of the results are presented in Figure 1.
Due to natural soil variations, tests results will be available on the vicinity of each pile.
Figure 1 – Some preliminary in situ tests
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3.2 Pile Load Tests
In the experimental site 3 different kinds of piles are to be loaded axially side by side by static
test. The localization of the piles is showed in Figure 2:
 10 bored piles (E0 to E9, circular section D=600mm)
 2 CFA piles (T1 and T2, circular section D=600mm)
 2 driven piles (C1 and C2, square section B=350mm)
The bored piles E1 to E8 are reaction piles with 22m of length. All the others are short piles with
6m of length.
Piles E9 (bored, L=6m), C1 (driven, L=6m) and T1 (CFA, L=6m) will be loaded by static test up
to failure. Piles E9 and E1 are fully instrumented with retrievable extensometers.
Similar piles: E0 (bored, L=6m), E2 (bored, L=22m), E6 (bored, L=22m), C2 (driven, L=6m) and
T2 (CFA, L=6m) were used for high strain dynamic load tests.
These tests offer a unique opportunity to study the installation effects by comparing the
behaviour of these piles up to failure. Besides, high strain dynamic load tests in similar piles are
available to allow comparisons with the static ones.
4. INVITATION TO THE PILE PREDICTION EVENT
The tests will take place very shortly. The bored and CFA piles were already installed in July.
The driven piles and high strain dynamic tests were performed in September and the static load
tests will take place in November 2003. We will make test results available to people who plan to
participate in this event soon after. If you know someone who could have interest to participate
please send this document and help us to promote this pile prediction event.
The auspices of ITC-18 (International Technical Committee on “Deep Foundations”, chaired by
Professor Holeyman) of the ISSMGE are being considered for this activity. One of the terms of
reference assigned to ITC-18 consists in addressing the influence of the installation method of
piles on their load-bearing behaviour under vertical compression. The activities of ITC-18 can be
followed on the following website: http://www.geoforum.com/tc18.
The support of Pile Dynamics, Inc to promote this event is also being considered
(http://www.pile.com/events/).
In the meantime, please let us know if you are interested to participate in the prediction event by
filling in the form attached and email, fax or mail to us.
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Figure 2 – Tests localization
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D
C
B
4.00
4.00
(22/05/03)
DMT5
(22/05/03)
DMT4
4.00
(23/05/03)
CPT4.1
PMT1
(10/9/03)
PMT1.0
1.75
2.00
2.00
2.20
A
(11/09/03)
S5
S4
E0
E1
E3
(11/09/03)
E5
E7
1
CPT6
E9
C1
CPT5
T1
C2
2.00
2
(10/09/03)
PMT2
0.20
2.00
3
E2
E4
E6
E8
T2
CPT3
DMT3
CPT2.1
CPT1
(09/09/03)
PMT
S2.1
S3 - SPT
S2*
SP2 DMT1
DPSH
S0 - SPT
S1 - SPT
DMT2
REFERENCE SLAB
DITCH FOR SEISMIC PROFILES
STATIC TESTS ON PILES:
E9, C1 & T1
(up to failure)
DYNAMIC TESTS ON PILES:
E0, E2, E6, T2 & C2
(high strain; vertical)
SITE CHARACTERIZATION
S - Borehole with Sampling
A - Undisturbed Samples
SPT; CPT; DMT; PMT; DPSH; SP
PILES
E - Bored (D=600mm)
T - CFA (D=600mm)
C - Driven (300mmx300mm)
LEGEND :
5. REFERENCES
“Characterising and deriving engineering properties of a saprolitic soil from granite, from Porto”. Chapter
of the book “Characterization and Engineering Properties of Natural Soils”. Ed. por Tan, Phoon, Hight &
Leroueil, publ. Swets & Zeitlinger, Lisse (ISBN 9058095371), Vol.2, pp. 1341-1378).
Viana da Fonseca, A., Fernandes, M. & Cardoso, A. S. (1997). “Interpretation of a footing load test on a
saprolitic soil from granite”. GÉOTECHNIQUE, Agosto de 1997, Vol. 47, No.3, pp. 633-651. Thomas
Telford, London. (ISSN: 0016-8505).
Viana da Fonseca, A., Fernandes, M. & Cardoso, A. S. (1998). “Characterization of a saprolitic soil from
Porto granite by in situ testing”. First International Conference on Site Characterization – ISC’98, Atlanta
, USA, 19-14 April, Vol. 2, pp.1381-1388, Ed. Robertson & Mayne. Pub A.A. Balkema, Rotterdam, Nth
(ISBN: 90-5410-941-6).
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Viana da Fonseca, A. (2001). “Load tests on residual soil. Settlement prediction for shallow foundation
design”. JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING American
Society of Civil Engineers (ASCE), Vol.127, nº 10, pp. 869-883, Reston, VA USA (ISSN: 10900241/01/0010-0817).
Viana da Fonseca, A. & Almeida e Sousa, J. (2002). “Hyperbolic model parameters for FEM analysis of a
footing load test on a residual soil from granite”. PARAM 2002: International Symposium on
“Identification and determination of soil and rock parameters for geotechnical design” 2-3 September
2002, Paris. Vol. 1, pp 429-443, Procceedings Ed. J-P Magnan, Presses L’ENPC (ISBN: 2-85978-363-6),
LCPC (ISBN: 2-7208-6003-4), Paris, FR.
Viana da Fonseca, A., Sousa, F. V. e & Ferreira, C. (2003). “Deriving stiffness parameters from “gross”
in situ tests and relating them with “noble” reference values on saprolitic soils from granite”, 12th
Panamerican Conference on Soil Mechanics and Geotechnical Engineering, MIT, Cambridge, USA. . Vol.
1, pp 321-328, Procceedings, Ed. Culligan, Einstein & Whittle. Pub. VGE, Verlag Guckuf GmbH (ISBN:
3-77739-5985-0), Essen, GE.
Sponsors:
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Expression of Interest to Participate in the
International Prediction Event
on the Behaviour of
Bored, CFA and Driven Piles in ISC’2 experimental site – 2003
Please check the item(s) below. You may wish to participate in: (1) Load-bearing behaviour
prediction based on in situ and laboratory tests and/or (2) Load-bearing behaviour prediction
based on high strain dynamic tests:
Yes, I will participate in
(Please check Prediction number)
(1)
(2)
No, I will not participate ______
I have not decided at this time but please keep me informed ______
Please type or print:
Name:
Affiliation:
Mailing address:
Email address:
Phone:
Fax:
Please email, fax or post the complete form before 10th of October 2003:
Fax: +351-218418427
Email: jaime@civil.ist.utl.pt
Address:
Departamento de Engenharia Civil
Instituto Superior Tecnico
Avenida Rovisco Pais, 1049-001
Lisboa
Portugal
Attention: Prof. Jaime Santos
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