Seismic lateral pressures for design of rigid walls

Design charts for seismic pressures against rigid walls subjected to horizontal earthquake shaking are presented for both uniform and nonuniform backfills. Solutions are based on a simplified model of soil response which gives results that agree almost exactly with rigorous solutions. Peak seismic thrusts are presented for three different soil profiles. For each profile, 250 combinations of ground accelerations and distributions of soil shear moduli with depth are analysed to provide data points of peak seismic thrust ratios for the construction of design envelopes. The seismic thrust ratios for design are presented as a function of the ratio of the predominant frequency of the earthquake motion and the fundamental frequency of the wall–soil system. An approximate method is given for evaluating the latter frequency without a full analysis.