SEISMIC ANALYSIS OF BURIED PIPELINE IN A 3D SOIL CONTINUUM

An efficient numerical approach based on both boundary and finite element methods is developed in this work. This development is capable of realistic three dimensional analyses of soil-structure interaction problems in the real time domain and is specifically tailored to buried lifelines. In particular, boundary elements are used in a surface-only representation of the buried cavity problem for determining influence functions at the cavity/pipeline interface for the case of prescribed motions at the control point. Subsequently, these influence functions are converted into loads and are used as input to a finite element model of the pipeline. Following careful validation studies, the present methodology is applied to a real site with known seismological characteristics and the results are gauged against empirical design formulae. It is shown that the seismically induced stress state in a buried pipeline is more pronounced in the case of transverse vibrations than in the case of longitudinal vibrations.