ON THE ASSESSMENT OF SOIL-STRUCTURE INTERACTION PROBLEM ON A CANTILEVER RETAINING WALL WITH A BASE KEY

Abstract

Retaining walls have an important role in terms of services in daily life such as quay walls, bridge abutment, wing walls, slope stability, and deep excavations. Assessment of the seismic analysis of cantilever retaining walls is an important issue in the field of geotechnical engineering since the experiences of past earthquakes worldwide show that the seismic vulnerability of these structures represents a potential source of significant economic loss due to structural failures and environmental accidents. In particular, the cantilever retaining walls located often on roads carry a risk under seismic loadings in point of transportation. In this context, dynamic response of the cantilever retaining walls has been the particular issue that many researchers have dealt with it for many years. This study investigates the dynamic response of a cantilever retaining wall with a base key considering soil-structure interaction. In accordance with this purpose, a 3-D finite element model is created by ANSYS software. The numerical model involves the foundation soil, retaining wall and backfill soil. Full transient seismic analyses are carried out considering four different foundation soil properties. The behavior of semi-infinite soil medium is taken into consideration with Lysmer-Kuhlemeyer type dampers putted on foundation and backfill faces. In such analyses, it is necessary to ensure that the boundaries of finite element model are sufficiently far removed from the structure that the full effects of radiational damping are correctly represented. The retaining wall-backfill interface is imitated with the springs which have bonding and debonding capabilities. Elasto-plastic behavior of the backfill and foundation soils is provided with the Drucker-Prager yield criteria, and hysteresis damping of the whole system is represented by Rayleigh damping. C02065 component of the 1966 Parkfield earthquake is used for the ground motion record in the analyses. Dynamic responses of the retaining wall are interpreted through horizontal displacements and stress values in the critical sections of the wall. The results show that the dynamic response of the cantilever retaining wall with a base key is affected considerably from decrement or increment of the soil stiffness, and soil structure interaction should be taken into consideration in design of the cantilever retaining walls.