Interaction of conical monolithic thin-walled reinforced concrete shells with the soil of the foundation and their stress state under the action of static loading
Authors:   Higher Educational Institution ", Panteleienko Volodymyr ,   Prydniprovska State Academy of Civil Engineering and Architec-ture",   , Ukraine, Karpushyn Serhii ,   Central Ukrainian National Technical University, Ukraine, Chervonoshta Andrii ,   Higher Educational Institution "Prydniprovska State Academy of Civil Engineering and Architec-ture", Ukraine
Published: February 2024

The use of monolithic thin-walled spatial reinforced concrete shells as founda-tions for low-rise technological or residential facilities is economically feasible, in terms of reducing the volume of earthworks. Compared to classical types of founda-tions, it provides a significant reduction of costs of concrete, reinforcement, and labor costs. However, the issues of interaction of monolithic thin-walled spatial rein-forced concrete shells with the base soil remain insufficiently researched. The work substantiates the dynamic model of the "hammer-head-shell-soil" sys-tem when interacting with the base soil. It demonstrates that it is reasonable to use the elastic-viscous-plastic model taking into account the attached soil mass. Based on that, the calculation scheme of this system was developed, considering the main connections between the colliding bodies and the interaction with the soil. Taking into account the above, the mathematical model "hammer-head-shell-soil" is developed and demonstrated, which is a system of nonlinear differential equations of second order. The solution of the system of equations gives the displacement and speed of all bodies, as well as the value of the forces acting on the contacts of colliding bodies at any moment of the time. The presence of an oscillating process in the "hammer-head-shell-soil" system was experimentally established. The headrest oscillations are unstable. They occur only in the event of impact and are extinguished as the load decreas-es. The analysis of the obtained dependencies when solving the mathematical model showed that the impact force is mainly determined by the height of the impact part and the stiffness of the elastic gasket. The ratio of the masses of the hammer and the shell has a smaller influence on the immersion process. The influence of the physical and mechanical properties of the soil base is insignificant. Despite the periodic nature of the force impact, the shell sinks into the soil base quite smoothly. This is explained by the significant mass of the shell, as well as the inertial stabi-lization properties of the soil base. To find out the qualitative regularities and the physical essence of the process of immersion of conical blocks in natural conditions, a specially designed stand was used, which made it possible to determine the shape and dimensions of the compact-ed zone in different soils. Concrete block designs of various types were developed and presented. A static load study using the "SolidWorks" program showed that concrete blocks can with-stand tests for fatigue failure, for loss of stability, and have a safety margin for de-formations that occur during loading. For the manufacture of concrete blocks, as the research on the material showed, it is advisable to use M300 concrete.