Assessment of Building-Foundation Interac-tion Using the Finite Element Method Based on Soil Compression Test Data

Summary. The article presents a methodology for assessing the interaction between buildings and their soil foundations based on data from soil compression tests widely available in engineering geological survey reports. The primary aim of the study is to develop an approach for accounting for soil compaction within the "Base-Foundation-Structure" system using the finite element method (FEM). This approach enables more accurate modeling of the stress-strain state of structures under pressure ranges typical for modern buildings, such as high-rise residential complexes or industrial facilities. The methodology proposed in the article considers the specific characteristics of soil deformation under loading, particularly the compaction processes that occur due to the reduction of porosity. The dependency of the deformation modulus on soil pressure is described based on experimental data from compression tests extended to higher stress levels using mathematical models. This eliminated the need for expensive and complex tests that are rarely accessible in the context of Ukrainian engineering practice. The study involves modeling the stress-strain state of a real-life object—a 25-story residential building in Kyiv. Two scenarios were analyzed: the traditional approach with a constant deformation modulus and the proposed methodology incorporating a variable deformation modulus. The modeling results demonstrated that considering soil compaction processes significantly reduces peak stress values in foundation structures and ensures a uniform distribution of bending moments in grillages. Special attention is given to assessing the height of the structurally disturbed soil zone beneath the foundation. It was found that this zone could reach up to 9 meters for grillages and 12 meters for pile foundations, depending on the applied load. The results suggest the necessity of embedding piles beyond this zone to ensure structural stability. The proposed approach is universal, as it is based on standard oedometer data and can be adapted to various soil types and structural configurations. The results demonstrate the practical value of the methodology for optimizing foundation design, reducing the material consumption of structures, and improving their reliability. Furthermore, accounting for soil compaction processes enhances the accuracy of engineering calculations and ensures the rational use of material resources in complex geological conditions. The calculation methodology proposed in this study can be integrated into modern software packages such as ABAQUS, significantly simplifying its implementation in engineering practice. This makes it particularly valuable for the design of high-rise buildings, industrial facilities, and other structures subjected to significant foundation loads.