Failures of Retaining Wall Structures Due to Earthquake

This paper describes crack pattern of reinforcement concrete retaining structure due to earthquake. For this reason, the 3-D finite element dynamic analysis of retaining wall structures with consideration of the soil-structure interaction has been used. Purpose of this study is to detect damage zone, due to earthquake in such structures. The analysis data is based on 1995 Kobe and 1994 Northridge earthquake reports, and the results have been verified with some retaining walls were damaged in those earthquakes. To take into account the non-linearity of soil-structure surface, surface to surface contact element is used. One of the most important problems in dynamic analysis is modeling of infinite media. If hinge or sliding support for soil boundary is used , it would not define an acceptable boundary condition, because the transmitted earthquake waves reflect from the boundary and no energy would transmit out. For simulation of the unbounded nature of the soil medium, viscous (dashpot) boundary has been applied. Damping coefficient is given by Lysmer and Kuhlemeyer, and Drucker Prager soil plasticity model is considered for non-linearity of soil. Distributions of the amplitude of stress in the wall, crack pattern in concrete wall are discussed in detail and finally suggested flexural failure diagram for determining damage zone and weak point of cantilever retaining wall