NONLINEAR SEISMIC GROUND RESPONSE BY CONSIDERING PORE PRESSURES AND DRAINAGE

Abstract

One part of the dynamic analysis is determination of spatial/temporal distribution of seismic ground response along the boundaries chosen for the system that include the structure and the surrounding medium. Seismic ground motion records indicate that spatial variations in ground motions can be significant, especially when the structure has a considerable length. Some structure like dam, bridge, nuclear power plant and under ground structures is critical from an overall viewpoint and the provision of'relief services after earthquakes. Thus it is very important to determine as precise as possible the spatial/ temporal distribution of the seismic ground response. The work described here in may be divided into two major parts the determination of spatial/temporal distribution of seismic ground response and the parametric studies. In this investigation, the seismic ground analysis is being carried out with due regard to pore pressure generation and dissipation due to drainage during the seismic motion. Computer program has been made for the analysis. The analysis described here has two part, in first part pore pressure generation has been carried out by making some modification in the Seed and Idriss method and the second part is pore pressure dissipation due to drainage by considering a system of vertical drains. Temporal distribution of seismic ground response is calculated for the above two cases and the comparisons have been made. Limited parametric studies have been carried out. Expected behaviour has been observed from the results obtained, which ' shows the credibility of the analysis.