This paper illustrates an original and simple method to predict earthquake-induced deformations of geotechnical systems. The method is an extension of static non-linear analysis, and is conceived to predict the behaviour of geotechnical systems, like supported and unsupported excavations, that during the seismic motion accumulate displacements in a single direction. The seismic capacity of the system is described by its capacity curve, obtained either from a numerical push-over analysis or through a simplified procedure. The corresponding seismic demand is described by a combination of the elastic response spectrum, including basic information on the maximum amplitudes of the seismic motion, and a cyclic demand spectrum, that provides additional information about the equivalent number of cycles that contribute to the accumulation of displacements. In the paper, the method is described in detail and is validated through different procedures, namely: comparisons with experimental results obtained in the geotechnical centrifuge; comparison with results of advanced numerical analyses; extensive comparison, using a large database of seismic records, with the results of non-linear time-domain analyses. In its final part, the paper provides guidance for the practical use of the method for design.

本文阐述了一种预测地震引起的岩土系统变形的简单方法。该方法是静态非线性分析的扩展，被认为可预测岩土系统的行为，如支撑和不支撑的开挖，它们在地震运动过程中会在单个方向上累积位移。该系统的抗震能力由其能力曲线描述，该曲线可以通过数值推覆分析或简化程序获得。相应的地震需求是通过弹性响应谱（包括有关地震运动最大振幅的基本信息）和循环需求谱的组合来描述的，该循环需求谱提供了有关等效位移数的附加信息，这些等效循环有助于位移的累积。在本文中，对该方法进行了详细描述，并通过不同的程序进行了验证，即：与岩土离心机中获得的实验结果进行比较；与高级数值分析结果进行比较；使用大型地震记录数据库进行广泛的比较，并进行非线性时域分析。在最后部分，本文为设计方法的实际使用提供了指导。