Algorithm to identify calculation dimensions for the ground foundation-underground and surface structures system

Purpose is to elaborate recommendations to identify horizontal dimensions for the calculation area of a ground foundation while defining a stress-strain state of the ground foundation-underground and surface structures system using a finite element method. Methodology. The research applied numerical approach to model a stress-strain state of the ground foundation-underground and surface structures system. To evaluate the impact by the calculation area dimensions, internal forces and displacements within the underground structure, foundation, and surface structure elements have been compared in terms of successive size increase. Differences between the results were assessed through relative and symmetrically relative mean-square errors. Findings. It has been defined that an increase in the calculation area dimensions up to the certain point results in the decrease of differences between the obtained internal forces and displacements. At the same time, further increase may stipulate their sharp growth and influence by the area dimensions is more essential for a base plate and underground structure, and less expressed for the surface structure columns. An algorithm has been proposed to determine the calculation area dimensions by means of their gradual increase and comparison of the related calculation results. A symmetric relative mean-square error value not exceeding 5% or its minimum value has been assumed as a sufficiency criterion. Originality. An approach has been developed to identify horizontal dimensions of the calculation area of ground foundations based upon a quantitative comparison of the changes in a stress-strain state of the system under successive increase in the area sizes. Practical value. The developed algorithm makes it possible to define reasonably dimensions of a calculation area of the foundation in the process of finite-element simulation of common action by ground foundation; and underground and surface structures.