Chef de projet : NOM Prnom - Repositório Aberto da Universidade ...

Premier Symposium Méditerranéen de Géoengineering «SMGE09» Alger 20 et 21 juin 2009
From the analysis of the deflections obtained on structures 1 and 2, it was possible to observe,
as expected, that the deflections on structure 1 are higher, when the treated soil layer is thinner.
Nevertheless, the difference is not significant, and, therefore, the interpretation was done using
only structure 1, i.e., the most unfavorable one.
Figure 4 depicts the deflection basin of structure 1, taking into account the various hypotheses
considered. Furthermore, the normalised deflections for 20 kN load of FWD tests performed in
situ on the treated soil (mixture with 4% of lime) are also represented (Pk26525 and Pk26550).
Figure 4. Deflections obtained with PLAXIS ® for different hypotheses (structure 1) and normalized
deflections for 20 kN load (layer with 4% lime)
The comparison of the different deflection basins – measured in situ and obtained with
PLAXIS® – allowed to conclude that the best fit corresponds to deformation modulus values of
lime treated soils of about 200 to 400 MPa.
The equivalent deformation modulus calculated using the maximum deflection obtained at the
Pk26550 test (375 μm) is 170 MPa. This value is higher than the one specified in the design.
3.2.2 Highway A10
The design of this highway specifies that the pavement substructure should present
characteristics that will ensure that the deformation modulus at the top of the capping layer
would be higher than 120 MPa at long term.
In a first stage, a test section was constructed in order to confirm if the substructure deformation
characteristics required in the design could be achieved, and also to assess the effectiveness of
the equipment used and to verify the homogeneity of the work performed. In a second stage,
two evaluation campaigns were performed on previously completed work sections.
As a result, and in accordance with the layout presented in Figure 5, the pavement structure is
expected to be as follows:
- the bottom capping layer of lime treated soils (LT1) with a 40 cm thickness;
- the top capping layer consist of two layers: a 20 cm layer of lime treated soils (LT2) overlaid by
a 20 cm layer of a well graded crushed aggregate (ABGC).