Holistic equivalent linearization approach for seismic response analysis of soil layers

The limitations of the traditional equivalent linearization approaches are investigated. The concept and algorithm of the holistic equivalent shear strain are proposed, and a new program for calculating seismic response of the equivalent linearized soil is compiled. The research indicates that the traditional approaches for the equivalent shear strain with 0.65 times the maximum shear strain are not suitable for simulating the shear stain of soil layers in strong nonlinear cases. Based on the holistic optimization, the participation and completeness of the holistic equivalent shear strain are constructed. The participation is determined by the effective shear strain threshold. All shear strain waves whose peak values exceed the threshold value are used to participate in the calculation to ensure the integrity of shear strain information, and the zero-crossing method is used to ensure that there is a unique relationship between the effective equivalent shear strain and the shear strain time history. By taking 1963 sets of records in the four types of sites with surface PGA from 0.04g to 1.21g in KiK-net underground arrays as samples to compare the new method with the other existing methods, the results show that the proposed concepts and formulas are correct and reasonable, and they can solve the problem of simulating strong nonlinear seismic amplification.