1651
Proceedings of the 18
th
International Conference on Soil Mechanics and Geotechnical Engineering, Paris 2013
1
Seismic design of retaining wall considering the dynamic response characteristic
Conception sismique des murs de soutènement compte tenu des caractéristiques de réponse
dynamique
Watanabe K.
Railway Technical Research Institute, Japan
Koseki J.
Institute of Industrial Science, University of Tokyo, Japan
ABSTRACT: Under the previous design standard, retaining wall and bridge abutment are classified under same category as a
retaining structure and same seismic design procedure is applied in Japan. However, there is a difference in the dynamic response
characteristic in that the effect of seismic earth pressure is larger than inertial force for a retaining wall while inertial force is the main
external force for a bridge abutment. In this study, therefore, we performed a series of shaking table model tests in order to evaluate
difference of dynamic response characteristic of each structure. The experiments revealed that the dynamic response characteristic of
retaining wall is largely affected seismic ground motion characteristics, while the dynamic amplification is not significant. On the
basis of the test results, a seismic design method using the Newmark method was proposed for the retaining wall. This new methods
provides reasonable displacement compared to the test results of shaking table tests and the actual residual displacement of the
damaged railway retaining wall after the 1995 Hyogo-ken nambu earthquake. This proposed method was employed in the new
railway design standard for retaining structure in Japan which was revised into performance-based design in January, 2012.
RÉSUMÉ : Au Japon, conformément aux normes de conception antérieur, les murs de soutènement et les piliers de pont sont classés
dans la même catégorie des structures de soutèneme
nt et les mêmes processus de conception s’appliquent. Toutefois, les
caractéristiques de réponse dynamique présentent une certaine différence. Au cours de cette étude, nous avons procédé à une série
d’essais de modèles sur table à secousses afin d’évaluer
la différence des caractéristiques de réponse dynamique de chaque structure.
Les expériences montrent que les caractéristiques de réponse dynamique des murs de soutènement sont fortement affectées par la
pression sismique des terres et les caractéristiques
de déplacement sismique des terres alors que l’amplification dynamique est
négligeable. Sur la base des résultats des essais, nous avons proposé l
’
utilisation de la méthode de Newmark pour les murs de
soutènement, Cette nouvelle méthode assure un déplacement raisonnable par rapport aux résultats des essais sur table à secousses et le
déplacement résiduel réel du mur de soutènement endommagé après le tremblement de terre de la préfecture de Hyogo-Ken Nambu.
Cette méthode est désormais utilisée au Japon par la nouvelle norme de conception de chemins de fer pour les structures.
KEYWORDS: seismic design, retaining structure, Newmark method, dynamic response characteristic
1 INTRODUCTION.
1.1
0B
Design standards for railway retaining structures
Several types of retaining structures are used in railways. In
addition to conventional structures, recent years have seen the
introduction of new types of structure like reinforced-soil
retaining walls and reinforced-soil bridge abutments as
technical progress is achieved in reinforced earth construction
methods.
Conventional type retaining walls and bridge abutments are
categorized as “soil
-
retaining structures”
and design procedures
for them were indicated in the railway structure design standard
(2000). Seismic design regulations were also indicated in the
railway structure design standard (1999) which were compiled
based on experience drawn from the 1995 Hyogo-ken nambu
earthquake.
The railway structure design standard (earth
structures, 2007) on the other hand provided the design method
for reinforced-soil structures such as reinforced-soil retaining
walls and reinforced-soil bridge abutments, because the
reinforced-earth construction method, originally applied to earth
structures was applied to higher-grade structures, which allow
little deformation against severe earthquakes.
The design method for retaining structures used in railways
therefore appeared in different design standards for these
reasons. Choice of a conventional retaining structure or a
reinforced-soil structure is made considering the importance of
the intended structure, its required performance and the
construction site conditions. Consequently, suggestions have
been made indicating that it is necessary to cover these
structures in the same design standard, which offers a means to
assess their performance with an equivalent index.
Pursuant to the above objective, the Railway Technical
Research Institute (R.T.R.I), under the guidance of Ministry of
Land, Infrastructure and Transportation, revised the soil
Type of structure
Reinforced-soil structure Retaining structure
Retaining
wall
Bridge
abutment
Reinforced-soil
retaining wall
train
Earthreinforcement
facing
train
train
geogrid
facing
P.21
geogrid
R.L
Cement-treated
approach block
Bridge abutment
(conventional type)
Reinforced-soil
retaining wall for
cutting
Retaining wall
(conventional type)
bedrock
backfill
Reinforced-soil
bridge abutment
girder
Approach
block
backfill
backfill
girder
Figure 1 Structures covered under the new soil retaining structure
standard (R.T.R.I, 2012)
