Behaviours of retaining walls during earthquake

Retaining of soils is one of the oldest problems of geotechnical engineering. The static anddynamic lateral earth pressures exerted on retaining structures have been studied for morethan two hundred years. The static lateral earth pressure theories of Coulomb(1776) andRankine(1857) form the basis for the design of most retaining structures. Retaining wallspossess the risk of failure due to seismic loads which may be greater than the anticipated staticloads. Determination of the the magnitude and the distribution of lateral earth pressure arecomplicated even for the static cases and under the influence of seismic loading, they areusually more complex. Existing seismic design methods are essentially extensions of staticlateral earth pressure theories. Presently, verification of these design methods for earthquakesare incomplete and highly desirable.The main purpose of this thesis is to discuss the determination of acceleration coefficientsused in pseudo-static analysis methods and to understand the responses and behaviours ofretaining structures during earthquakes. In part 2 of the dissertation various types of retainingstructures and their application fields are explained. In part 3 of the dissertation, kinds oflateral earth pressure that may act on retaining structures and most common approaches tocalculate the lateral pressures are explained briefly. Furthermore, external forces that act onretaining structures and the effects of those forces on lateral earth pressure are presented inpart 4. In part 5, the stability checks that have to be applied to all kinds of retaining structuresare explained. In part 6, the behaviour of retaining structures during earthquakes and thelateral earth pressures calculated with the help of pseudo-static methods are explained. M-Omethod which is the baseline of the pseudo-static methods are discussed in detail and thedevelopment of pseudo-static methods are briefly explained in a chronological order.Furthermore, the displacement based design methods used for retaining structures, in additionto force based design methods are discussed. In part 7, the results of pseudo-static methods ontypical retaining walls and the results of dynamic response analysis performed using finiteelement methods are presented and compared.Key Words : Retaining Structures, lateral earth pressure, stability of retaining structures,acceleration coefficient, pseudo-statik methods, finite element method