SEISMIC RESPONSE OF RETAINING WALLS",

Abstract

Earthquakes have caused permanent deformation of retaining structures in many historical earthquakes. In some cases, these deformations were negligibly small; in others they caused significant damage. Evaluation of the performance of retaining soil structures subjected to seismic loading, whether in the field or in laboratory model tests, provides insight into the behavior to be considered in design. Retaining walls are susceptible to failure if their responses under static and dynamic conditions are not properly predicted and designed accordingly. Therefore, while designing retaining walls, stress and displacement criteria become important. For analysis and design of retaining walls magnitude and distribution of earth pressure and displacement of the wall under static and dynamic conditions is required. In this dissertation, the problem is analyzed in static as well as dynamic conditions. Stresses and displacements for static case are calculated by conventional methods, which have been giving satisfactory results for all these years. The response of structure in static conditions is also found out by finite element analysis with use of software package, ANSYS. Comparisons of all these are plotted and results are tabulated. For the dynamic case the most conventional method available to us today is the pseudostatic method suggested in IS: 1893 — 1984 (reaffirmed 2003). But, being a pseudostatic method it is observed to overestimate the stresses. For the problem at hand, time history analysis with Uttarkashi Earthquake motion data used for the purpose. Dynamic increment plots are drawn which give us an idea of the effect of dynamic forces on total stresses. Displacement response at the top of wall, bottom of heel slab and bottom of toe slab are worked out together with slip and separation at these locations.