Frequency-Dependent Dynamic Characteristics of the Soil Foundation

Grounds and foundations, underground structures

.The object of the research is the dynamic characteristics of the soil foundation used for calculating structures for seismic loads. The purpose of this work is a comparative analysis of dynamic characteristics for different types of soils. The impact of the embedment of the foundation is also assessed. The article compares the normative and finite element methods of calculation. Method. The dynamic characteristics are determined from the solving of the task of harmonic vibrations of a stamp on an elastic half-space. The finite element model was verified using an analytical solution. To simulate an infinite region in the limited volume of soil, elements that absorb the energy of vibrations (Perfectly Matched Layer) were used. Results. Verification of the finite element model showed an acceptable error with an analytical solution. By solving a number of problems, it was found that the normative formulas for calculating dynamic characteristics give correct values only for low-frequency effects. Comparison graphs show a sharp increase in the frequency dependence of characteristics when soil conditions degrade (the shear wave velocity decreases).