EVALUATING THE SEISMIC BEHAVIOR OF AN L-SHAPED CANTILEVER RETAINING WALL CONSIDERING SOIL-STRUCTURE INTERACTION

Abstract

The dynamic behaviour of the cantilever retaining walls having a wide range of geometries can be quite complex in spite of their structural simplicity. Although it is clearly known that the dynamic response of the cantilever retaining walls is affected by many factors such as the foundation soil, backfill soil properties, wall geometry, and earthquake ground motion characteristics, it is still a confusing question to what extent these effects change the behaviour. In this context, the dynamic behaviour of the L-shaped reinforced concrete cantilever retaining wall is investigated by means of a numerical model considering soil-structure interaction in the study. In the numerical modelling, the finite element method is used, and this model is constructed to include three systems: the foundation, structure and backfill soil. To provide the discrete behaviour of the wall-backfill system, nonlinear springs are defined on their interface. In addition, the nonlinear behaviour of foundation soil systems is taken into account with Drucker-Prager yield criteria. In order to get rid of the effects of the wave reflection and to attempt to produce infinite boundary behaviour, the viscous dampers are placed on the boundaries of the soil medium considering the guidance of Lysmer and Kuhlemeyer dashpot boundary. The dimensions of the foundation soil domain is selected big enough to curtail down the reflections from the lateral boundaries. The hysteresis damping of the whole system is provided in the form of Rayleigh damping. The analyses, which consider C-OLC360 component of the 1983 Coalinga earthquakes, are performed as full transient, and four different foundation soil systems are taken into consideration in these analyses. The results are examined for displacements along the wall height and stresses in the critical section of the wall. The results show that the soil-structure interaction significantly affects the wall dynamic responses due to the decrease in the foundation soil stiffness.