Assessment of the influence of surface soil layers with nonlinear properties on the parameters of maximum response spectra

The methods of setting initial seismic effects in co-modern normative documents of different countries are described. The seismic impact is specified in the form of maximum spectra for rocky or rigid soils. To take into account local geological conditions, correction ground coefficients are used, which do not always correctly describe the amplification of vibrations. A methodology has been developed that makes it possible to take into account the influence of soft soil layers with consideration of nonlinear behavior on the parameters of the maximum response spectra. The nonlinear behavior of the ground is taken into account by means of an iterative nonlinear method equivalent to the nonlinear method. The method of solving problems of elasticity theory and structural mechanics based on the properties of Fourier spectra of finite functions is used in the construction of the method. For a two-layer soil massif located on the bedrock, a system of equations for calculating the amplification coefficients of the spectra of maximum reactions by surface layers of soils is obtained, which allows to estimate local engineering geological conditions more accurately.