EQUIVALENT LINEARIZATION TECHNIQUE BASED ON DISCRETE SHEAR-SLICE MODEL FOR NONLINEAR SEISMIC RESPONSE OF EMBANKMENTS
堤坝非线性地震响应的离散型剪切条模型等价线性化方法

As a simplified analytical procedure,the shear-beam or shear-slice model is widely employed for evaluating dynamic response of earth dams or embankments.In order to improve the accuracy or extend the range of this simplified model,many efforts have been made in the past several decades.A modified equivalent linear technique for analysis of seismic response of embankments,which is based on one-dimensional shear-slice model is presented.In the proposed method,the discrete shear-slice model is developed to consider the layered distribution of shear moduli and damping ratios of soils with depth.The differential equations for governing the vibration of embankment are solved mathematically under the assumption that the soils of embankment display visco-linear-elastic behavior;and the closed-form solutions for the natural characteristics and seismic response of the embankment are obtained.The achieved linear solutions are incorporated with equivalent linearization technique for seismic response of embankment or soil strata.A series of trial-and-error iterations are performed to make the moduli and damping ratios of all individual layers be compatible with their strain amplitudes.Then,a linear system which is overall equivalent to nonlinear embankment system is achieved;and the seismic response for this equivalent linearization system can be taken as a good approximation of nonlinear seismic response of embankment.Finally,numerical computations are conducted for a given example and the numerical results are compared with the solutions obtained with finite element method to illustrate the rationality of the proposed method.