Development and Justification of a Spatial Mechanical Model of the Foundation of Structures with the Given Design Characteristics of Soils, Taking into Account the Final Stiffness of the Foundation Structures

Abstract

To determine the magnitude of the internal forces in sections it is necessary to justify the design of the foundations of structures. Considering the flexibility of the foundation using the finite element method it is necessary to establish the law of distribution of quasistatic and viscous stiffness of the soil base on the bottom of the foundation slab.

Parameters of the base model should essentially simulate the reaction parameters of the base of a rigid weightless stamp with its unit displacements and speeds (linear and angular) along and relative to the coordinate axes.

The parameters of the foundation and the law of the distribution of integral stiffness on the contact surface are determined and justified. By the comparing the analysis of RO soil-structure systems with parameters established according to [1] and [2], the reliability of the developed model is substantiated.

A new 3D mechanical dynamic model of the foundations of nuclear power plant structures is proposed and approved.

Nowadays the model of the nuclear power plant structures foundations given in ASCE 4-98 is widely used. There is a dependence between the viscous stiffness of the foundation and mass and inertia moments of the structure during rotational movements of a rigid weightless stamp on the surface of an inertial half-space in this model. This contradicts the physical essence of the concept of viscous stiffness.

In the light of the foregoing, the development of a dynamic mechanical model of a foundation that eliminates the aforementioned discrepancies seems to be an important task of undoubted scientific and practical value.