1959
Influence of facing vertical stiffness on reinforced soil wall design
Influence de la rigidité verticale du parement dans la conception des murs en sols renforcés
Damians I.P., Lloret A., Josa A.
Universitat Politècnica de Catalunya (UPC) – BarcelonaTech
Bathurst R.J.
Royal Military College of Canada
ABSTRACT: Current design practices for reinforced soil walls typically ignore the influence of facing type and foundation
compressibility on the magnitude and distribution of reinforcement loads in steel reinforced soil walls under operational conditions. In
this paper, the effect of the facing vertical stiffness (due to elastomeric bearing pads placed in the horizontal joints between panels) on
load capacity of steel reinforced soil walls is examined in a systematic manner using a numerical modelling approach. Numerical
modelling was carried out using the commercial finite element program PLAXIS. The numerical model was verified against
measurements recorded for an instrumented 6 m-high wall reinforced with steel strips. The influence of the facing stiffness and
backfill-foundation stiffness combinations on the vertical load through the facing and on the magnitude and distribution of the
reinforcement loads was examined. For walls subjected to operational (working stress) conditions at end of construction, the
numerical results confirm that the vertical stiffness of the facing and soil-stiffness combinations can have a great effect on the vertical
facing loads and on the magnitude and distribution of the load mobilized in the soil reinforcement layers.
RÉSUMÉ: Les pratiques actuelles de conception des murs en sol renforcé ignorent généralement l'influence du type du parement et de
la rigidité de la fondation sur l'ampleur et la répartition des charges de renforcement. Dans cet article, on utilise une approche par
modélisation numérique pour examiner systématiquement l'effet de la rigidité du parement vertical (due à la présence de cales en
élastomère placées dans les joints horizontaux entre panneaux) sur la capacité de charge des murs renforcés sol/acier. La modélisation
numérique a été réalisée à l'aide du code commercial Éléments Finis PLAXIS. Le modèle numérique a été validé sur des mesures
enregistrées lors de l’expérimentation d’un mur d’une hauteur de 6 m et renforcé par des bandes d'acier. Le modèle permet de tester
l’influence de différentes combinaisons entre la rigidité du parement et celle du remblai-fondation sur les valeurs des charges
verticales dans le parement et les efforts dans les éléments de renforcement. Pour les murs travaillant en conditions opérationnelles
(sous efforts de service) à la fin de leur construction, les résultats numériques confirment que ces combinaisons ont un grand effet sur
les charges verticales et la distribution des efforts mobilisés dans les couches de renforcement.
KEYWORDS: reinforced soil retaining walls, steel strips, facing panels, finite element modelling.
1 INTRODUCTION AND GENERAL APPROACH
The mechanical behaviour of reinforced soil walls is
complicated due to the mechanical complexity of the
component materials (including soil type/arrangement), their
interactions, wall geometry, and the influence of method of
construction. Most reinforced soil walls are designed assuming
that the wall foundation is rigid and/or does not influence the
magnitude and distribution of reinforcement loads under
operational conditions. This assumption may not apply to walls
constructed over compressible foundations. This paper
describes the results of a series of numerical simulations that
were carried out on a 6-m high wall with precast concrete
panels with metallically reinforced soil and constructed with
backfill (reinforced soil and retained fill) and foundation soils
having different stiffness, and different number of horizontal
joints (i.e. different height of the panel units) along the facing
elevation.
The program PLAXIS (PLAXIS 2008) was used to carry out
the numerical simulations. The reference case for model
calibration is the instrumented 6 m-high precast panel facing
wall reinforced with steel strips reported by Chida and
Nakagaki (1979). All the results in the present study correspond
to operational (working stress) conditions at the end of the
construction.
2 NUMERICAL MODEL
2.1
General
The PLAXIS global geometry, structural components, and the
numerical mesh to simulate the performance of the reference
instrumented case are illustrated in Figure 1.
H
= 6 m
L
≈ 4 m
10 m
10 m
11 m
Foundation
Precast facing panels
(Detail)
Leveling
pad
Panel
Panel
Bearing
pad
Soil-facinginterface
Soil-reinforcementinterface
Reinforcement
Detail
Reinforcements
Backfill
Figure 1. PLAXIS numerical model
