A Method Of Estimating The Overall Nonlinear Dynamic Properties Of Layered Poroelastic Sites

For the purpose of predicting strong obliquely incident earthquake groundmotion of an engineering site with unknown soil properties (called unknown site), thispaper, as an alternative, proposes a method of estimating the overall nonlinearity ofthe unknown site in layered poroelastic half-space with elastic rock in purpose ofpredicting strong obliquely incident earthquake ground motion of an engineering sitewith unknown soil properties (called unknown site), in which, an adjacent referencesite with known linear and nonlinear soil properties is introduced, and both theunknown site and the reference site are assumed to have the same horizontal andvertical bedrock outcrop motion. Compared with the elastic field, the estimation of theoverall nonlinearity in the saturated site involves more parameters and more complexproblems. In the period of the estimation, the weak and strong earthquake records,which are only at the surface of the unknown site and the reference site, are used forestimating. By selecting two neighboring actual sites in Tianjin (a site as the reference,a site as the unknown), the paper estimates the overall nonlinearity of thesaturated-unknown site, and verifies the method by an example of incident waves. Itis shown that the method can accurately estimates the overall nonlinearity of sites andpredicts strong seismic ground motion, and the method can be directly applied in theengineering practice. Meanwhile, the paper provides a comparation with the results ofestimating the overall nonlinearity of saturated sites depending on equivalentone-layer and three-layer method, including the overall contrast and error analysis inthe soil properties.