Seismic Response of Embedded Retaining Wall for Excavation Support

Abstract

A comparative analysis of the solutions for the seismic impact on a flexible retaining wall designed to strengthen the construction excavation for a multi-storey building in Sofia has been performed. For this purpose, the following FEM calculation models of the interaction of the wall with the surrounding soil body were compiled: (1) a 1D beam-column-spring model of the wall, including spring support in its embedded length and pseudostatic seismic loading of the wall with active earth pressure, determined by the Mononobe-Okabe method; (2) a 2D model of the wall and soil body, with pseudostatic seismic loading in the form of inertial forces applied at the finite element nodes; (3) a time history FE analysis conducted with the accelerograms of two landmark earthquakes from the Balkan Peninsula - the 1976 Vrancea (Romania) earthquake and the 1986 Kalamata (Greece) earthquake. The pseudostatic seismic loading in analyzes (1) and (2) was determined on the basis of the reference pseudostatic acceleration of 2.3 m/s2, determined for the city of Sofia according to the seismic hazard map for Bulgaria. The accelerograms in analysis (3) were scaled to a maximum value of acceleration of PGA = 2.3 m/s2. The physical modelling of the soil body uses the HSM and HSsmall advanced constitutive laws, implemented in the Plaxis software.