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Introduction. A calculation scheme of karst sinkhole in karst territories using the results of laboratory experimental studies is developed, which makes it possible to determine the shape and size of karst sinkhole depending on the karst cavity dimeter (radius), its depth, the base slope angle and the angle of internal friction of soils composing the slope.Materials and methods. The method of calculation of normal contact stresses in the sloping soil base under the bottom of the cross-beam foundation during the formation of karst sinkholes is given, considering three main cases of karst cavity location in the slope massif with the most unfavourable location of the karst cavity relative to the cross-beam foundation structures.Results. The analytical dependence allowing to determine the theoretical value of the design value of the diameter Lc of the cavity in the sloping base is obtained, as well as to establish the main design dependences for determining the normal contact stresses, which allow to estimate the changes in the VAT parameters of the cross-beam foundation operation after the cavity vault collapse and formation of a complex shape of the collapse funnel.Conclusions. The developed methodology is convenient to use for qualitative assessment of design solutions in the design of cross-beam foundations on a sloping base in karst-prone areas. The obtained variant design values of the main VAT parameters according to the proposed methodology will allow to apply rational design solutions in design.

The article observes different methods of coating the phosphor screens on the tritiated titanium matrices for creating the solid-state radioluminescent light sources (SRLS). Technology of SRLS is alternative to the existing technology of the gas-filled radioluminescent light sources. The main idea of SRLS is in bonding the working isotope (tritium) in the solid matrix and combining it with the phosphor. The key problem of SRLS is to provide the closest contact between the tritiated carrier matrix and phosphor screen. The basic requirements for the phosphor screens for SRLS would be the strength of fixation on the plate, uniformity and radiological and thermal stability. There have been made a comparison of various techniques of coating and fixing the phosphor screens by their effect on spectral and brightness characteristics of SRLS. The improved sol-gel technique of suspended sedimentation of phosphor screen from the potassium water glass binder solution was developed. The composition of the solution was established experimentally and we get the strong and uniform experimental prototypes of the glass coated phosphor screens of various thickness. The developed technology allows to deposit the strong and uniform phosphor coatings without using any additional dispersing agents. Screen thickness regulates by the amount of phosphor in the suspension. Also the optimal thickness of the phosphor screen, giving the maximum luminescence intensity was determined. The two laboratory prototypes of solid-state radioluminescent light sources were manufactured by coating the phosphor directly on the tritium β-source.