1603
Shaking table test of large-scaled slope model subjected to horizontal and vertical
seismic loading using E-Defense
Tessai sur table à secousses de modèles de gros talus par une accèlèration vericale et horizontale
par E-Dèfense
Shinoda M., Nakajima S.
Structures Technology Division, Railway Technical Research Institute, Tokyo, Japan
Nakamura H.
Seismic Safety Division, Japan Nuclear Energy Safety Organization, Tokyo, Japan
Kawai T.
Department of Civil Engineering, Tohoku University, Sendai, Japan
Nakamura S.
Department of Civil Engineering, Nihon University, Fukushima, Japan
ABSTRACT: This paper describes a series of shaking table test of a large slope model subjected to vertical and horizontal seismic
loading. The slope model was constructed using mixed material with silica sand and bentonite clay. A number of accelerometers and
displacement transducers were set to measure the response characteristics of the slope model. Input waves used in the shaking table
tests were sinusoidal and observed waves recorded near an actual nuclear power plant. The test results clearly show that a critical
direction of the vertical and horizontal accelerations exists, which is a factor to decrease the slope stability.
RÉSUMÉ : Cet article décrit une série d’essais sur table à secousses de modèles de gros talus soumis à une accélération verticale et
horizontale. Les modèles de talus ont été construits à l'aide d’un mélange de matériaux incluant du sable siliceux et de l’argile
colloïdale. L’installation de divers accéléromètres et capteurs de déplacement a permis de mesurer les caractéristiques de réponse des
modèles de talus. L’onde incidente utilisée dans les essais sur la table à secousses était une onde sinusoïdale et l’onde observée a été
mesurée près d’une centrale nucléaire. Le résultat des essais montre clairement qu’il existe une direction critique de l’accélération
verticale et horizontale qui entraîne une déstabilisation du talus.
KEYWORDS: slope, stability, shaking table.
1 INTRODUCTION
In 2006, the geguralory guideline for aseismic design of nuclear
power reactor facilities was revised in 2006. In this regulatory
guide, it is specified that the facilities shall be designed about
the phenomenon accompanying an earthquake after having
considered the collapses which can be assumed at a slope
around the facilities and tsunami enough. Both of them were
made the target of the judgment already as before, but it is
specified in the new regulatory guide newly this time. Therefore,
it is necessary particularly to evaluate a slope stability subjected
to an earthquake.
In the current regulatory guide, slopes to be carefully
considered are within 50 m distance between the toe of the
slope and the interest nuclear power plant and having within 1.4
times height of a slope which possibly cause the nuclear power
plant damage when occurring failure. In Japan, there are 54
nuclear power reactor plants constructed at 18 areas. Among all
of the nuclear power reactor plants, the number of the related
slopes to be carefully considered becomes 13 areas with various
slope heights ranged from 10 m to 200m of the order magnitude.
Conventionaly, for stability evaluation of natural slopes
around a nuclear power plant, a safety factor based on a limit
equibirium method has been used to check the safety of the
natural slope against a design seismic excitation. Even though
the calculated safety factor exceeds 1.0, a degree of collpase
varies a great deal depending on physical properties, mechanical
properties, geometry of the natural slope. Under the above
instructions of the revised guideline, the stability evaluation of
the natural slope around the facilities should be developed to
considered a degree of a displacement due to instability of the
natural slope subjected to a seismic load in addition to the
conventional evaluation based on the limit euqilibrium method
with the safety factor.
This paper describes a series of shaking table test of a large
slope models subjected to vertical and horizontal acceleration
using a three dimensional full-scale earthquake testing facilities
named E-Defense to develop the above evaluation method.
2 FAILURE MODE OF SLOPE
Our research group conducted over 20 cases of shaking talele
test to investigate deformation and response characteristics of
several types of slopes subjected to seismic load. From the past
investigation, it is revealed that a slip surface coule be observed
in the following pattern:
1) Slip surface is generated from top to bottom of the slope.
2) Slip surface is generated in the surface layer.
3) Slip surface is generated at the tip of the slope.
4) Slip surface is generated at the top of the a
slope.
Moreober, a sliding failure mode of slope subjected to seismic
load was classified as quick sliding mode, slow sliding mode
and quick sliding mode after slow sliding mode as those
intermidiate.
From the past shaking table tests, only horizontal acceleration
were applied to the slope models due to the specification of the
shaking table. Ling el al. (1997) pointed out the vertical
acceleration has a significant effect on the calculated factor of
safety and yield acceleration of steep slope. Therefore, in this
research, a large shaking table test was conducted to evaluate
the effect of vertical seimic load against the dynamic response
and failure mode with an unique slope model under the
horizontal and veritcal seismic loading condition.
Es ai sur table vibrante de talus de grande taille oumis à des ac élérations ticales
et horizontales
