ANALYSIS OF THE COMBINED STRUCTURE OF THE SHAFT OF THE DNIPRO METRO BY THE FINITE ELEMENTS METHOD

Purpose. The development of construction of underground excavations of the Dnipro Metro requires analysis and scientific substantiation of design solutions based on technologies that are new for Ukraine. The aim of the scientific article is to analyze the combined design of the shaft of the Dnipro Metro by the finite element method with determination of force factors in the linings of the pile system and shotcrete system with further substantiation based on the results of design solutions to the real situation of Dnipro Metro construction. Methodology. Two finite element models were constructed for the analysis of the shaft № 1 of the Dnipro Metro by the finite element method. They reflect the combined design of the shaft, which consists of two parts. The finite-element model of the pile system, which reflects the shell of bored piles, supported by a cap beam and ring beams, is analyzed separately. The model for the shotcrete system, which is used for the second part of the shaft, which lies in a solid rock mass, is separately modeled and analyzed. Finite-element models of both systems are assigned real deformation and geometric parameters, as well as the load, which became the key to adequate calculations by the finite element method. Findings. During the numerical analysis of the combined structure of the shaft № 1 of Dnipro Metro, the force factors (normal forces and bending moments) for the pile system and the shotcrete system were determined. These results became the basis for the reinforcement of both systems. Originality. A numerical analysis of the shaft structure was performed, which provided a complete picture of the force factors that allow predicting the appearance of normal forces and bending moments in similar engineering and geological conditions. Practical value. The results of the analysis of the combined design of the shaft of the Dnipro Metro by the finite element method allowed to scientifically substantiate the design solutions and ensure high performance of both shaft systems № 1.

ALGORITHMIC PROCEDURES FOR CONSTRUCTING ONTOLOGICAL REPRESENTATIONS OF PRODUCTION TECHNOLOGIES

This paper focuses on formalized description of technologies as a category of procedural knowledge. It describes the model of ontological representation of technologies. The authors present the algorithms of staged combined design of unified decomposition constructions that enable to form decomposition structures of technologies. The article introduces the extended algorithm to construct ontological representation of technologies.

STUDY OF PERIPHERAL REFRACTION IN CHILDREN WITH MYOPIA WITH ORTHOKERATOLOGY LENSES OF COMBINED DESIGN

Progressive myopia is a leading problem in modern optometry and ophthalmology in general. In recent years, refractive therapy with orthokeratology lenses has gained popularity among methods to control myopia progression. The aim: To study peripheral refraction in children with myopia with the use of orthokeratology lenses (OKL) of combined design. Methods. We followed up 60 children (117 eyes) diagnosed with uncomplicated mild to moderate myopia. All children underwent a complete ophthalmological examination as well as corneal keratotopography and peripheral refraction determination. Statistical analysis of correlations between peripheral corneal refraction under the influence of OKL, peripheral defocus, and axial length growth gradient was performed. Results. An inverse correlation relationship of -0.2 (p=0.03) was obtained between corneal differential power in the return 6 mm zone and peripheral refraction in its corresponding peripheral refraction of 23° on the temporal side. A positive correlation with a correlation coefficient of 0.21 (p=0.026) was obtained between the defocus in the temporal part and the gradient of myopia progression over one year, while the same result was obtained in the nasal part with a correlation coefficient of 0.2 (p=0.036). Concluсions. Difference corneal power at the periphery may be prognostic in relation to the course of myopia in OКL users. With an aboveaverage pupil diameter, combined design orthokeratology lenses are more effective in controlling myopia due to the greater influence of the formed corneal refractive ring on peripheral refraction.

THE INFLUENCE OF IMPROVED PLACEMENT OF FLOW-REGULATING FOREST BELTS ON THE FORMATION OF SURFACE RUNOFF OF MELTWATER

The materials of scientific research for a number of years on the formation of melt water runoff on autumn plowing with stock-regulating forest belts of a combined design with low-growing shrubs are presented. It was revealed that the spring runoff depends on the main natural factors: moisture, soil freezing and snow deposition.