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A finite element modeling study on the seismic response ofcantilever retaining walls

Ertuğrul, Özgür Lütfi
A numerical study was performed in order to investigate the effects of base excitation characteristics (peak acceleration amplitude and frequency of the excitation), soil strength and wall flexibility on the dynamic response of cantilever earth-retaining walls. In this study, Plaxis v8.2 dynamic finite element code was used. Previous 1-g shake table tests performed by Çalıan (1999) and Yunatçı (2003) were used to compare the experimental results with those obtained by finite element analysis. Comparison of experimental and numerical results indicated that the code was capable of predicting the dynamic lateral thrust values and bending moment profiles on the wall stems. In the light of these validation studies, a parametric study was carried on for a configuration that consists of an 8 meters high retaining wall supporting the same height of dry cohesionless backfill. Total and incremental dynamic thrust values, points of application and dimensionless bending moment values were presented together with the results obtained from commonly used pseudo static Mononobe-Okabe method and Steedman-Zeng approaches. According to the finite element analyses results, total dynamic active thrust act at approximately 0.30H above wall base. Base motion frequency becomes an important factor on magnitudes of dynamic active thrust when it approaches to the natural frequency of the system. Significantly high overturning moments were predicted at wall base in this case. It was observed that increasing wall rigidity causes an increase in forces acting on the wall stem during dynamic motion.