Resource-Saving Technologies for Restoring the Load-Bearing Capacity of Building Foundations Damaged as a Result of Non-Design Influences

Abstract

As a result of non-design influences on buildings, aboveground and underground parts of building structures are damaged and require comprehensive repair or replacement. For restoring the cross-section of foundations and increase the bearing capacity attributed local repair of concrete and reinforcement of foundation elements, reinforcement in the form of additional foundation beams, slabs, foundation grillage, construction of new foundations (including pile foundations) with the transfer of part of the load from damaged areas to them. Deep Soil Mixing technology is one of the most effective modern methods of stabilization of bases and reinforcement of foundations. Its advantages include effectiveness in confined spaces, minimisation of vibrations and the need for rapid construction to restore the load-bearing capacity of building foundations. Deep Soil Mixing involves the mechanical mixing of natural soil with binding materials (cement, lime, ash additives, etc.) without removing the soil to the surface. This results in the formation of monolithic soil-cement elements – piles, walls or arrays – which significantly increase the load-bearing capacity of the foundation and reduce its deformability. The article describes the method of strengthening of a building damaged by a combat missile strike. The foundation basics of this building lost its load-bearing capacity due to significant waterlogging during firefighting in the building. Proposed method involves the installation of additional soil-cement piles, which are connected to the existing foundation structure of the buildings by a monolithic reinforced concrete foundation grillage. The results of finite element modelling of the stress-strain state of soil-cement piles presented in the article revealed the combined action of the reinforcement frame and the soilcement pile mass, which is a fundamental principle for DSM piles that are reinforced to increase their bearing capacity; stress concentration in the upper part of the pile (near the head), which coincides with the area of most intense intervention when connecting a new pile to an existing grillage; the importance of lateral pressure and soil friction for the bearing capacity of the pile, which is particularly relevant since the technology does not involve soil removal, which does not reduce internal stresses in the soil mass compared to drilling methods of pile installation.