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.
