Construction and Geotechnics

The article considers the identification of potential sources of formation of water and mudflows in the area of the Olympic objects of the southern slope of the Psekhako ridge and the catchment areas of the 1st, 2nd and 3rd Galion rivers (the catchment area of the Mzymta river). The collection and study of natural, climatic and morphological characteristics mudflow basins and the study of the possibility of their negative impact on the operated Olympic facilities, the creation of a database of mudflow basins. Implementation of the results of studies of the natural-climatic and morphological characteristics of the mudflow basin of the river. Mzymta is assumed in the justification of anti-mudflow measures to protect the infrastructure of operated Olympic facilities from the negative impact of water and mudflows. To ensure the reliability of the functioning of these foundations and foundations of structures. It is important to take into account the possibility of a negative impact on them of water and mudflows that form in the conditions of mountainous terrain and natural and climatic features of this region, as well as due to the extremely insufficient knowledge of the current state of development in these territories. mudflow processes and the possibility of their activation as a result of the impact on the natural landscapes of mudflow basins during the operation of the foundations and foundations of Olympic facilities and their infrastructure (access and technological roads, power lines, ski slopes, chairlifts, various sites, etc.). Taking into account the impact of the consequences of a large-scale technogenic impact on the natural landscape, in the territory of operation of the Olympic facilities along the southern slope of the Psekhako ridge, the materials of the survey confirm the conclusions about the increased mudflow hazard of the watercourses of the river. Rudnichny, r. Sumasshedshiy, r. Kamburovsky. The main reason for the descent of these mudflows is the technogenic impact on the upstream natural landscapes, including the discharge of liquefied soil dumps from steep slopes, the concentration of surface runoff into concentrated eroded, cuts, etc. Simulation modeling of the stability of the river slopes was performed. Tobias, the most dangerous combinations of impacts under static and seismic conditions, to predict the formation of mudflows.

This article is aimed at studying methods for optimizing the pile field in order to ensure the greatest use of the bearing capacity of piles, adopted in the project, considering the most unfavorable design combinations of forces. The object of the study is a multi-storey apartment building on a slab-pile foundation with a regular grid of piles, which clearly shows the imperfection of the calculation methods, due to the incomplete use of the bearing capacity of a significant number of piles, but the methods described in the article are also applicable to other buildings on slab-pile foundations, especially the difference between the original scheme and the optimized scheme will be clearly visible on the example with longer piles in less bearing soils, spread over the entire depth of the foundation. The purpose of this study is to study methods for optimizing a pile field, to study the methodology for using these methods on a specific example and compare them in terms of the parameters of using the bearing capacity of piles: the absolute and relative value of the minimum load on the pile, the absolute and relative value of the maximum load on the pile, the absolute and relative value average load per pile, as well as their comparison of economic efficiency. In the course of the article, numerical modeling was used, using the finite element method and analysis of the results of multivariate calculation. The result of this article is the application of pile field optimization methods to the multi-storey building on a slab-pile foundation, the evaluation of each of the methods and their comparison according to these indicators, as well as an understanding of the further development of this topic.

The object of the study is paint and varnish coatings of cement concrete. The goal is to evaluate the stress-strain state of coatings under the action of temperature depending on the geometry of the substrate roughness relief. The results of calculating the distribution of stresses over the cross section of the coatings and the possibility of their peeling are presented. The SCAD Office software module was used for the calculation. Heavy concrete was considered as the substrate. Polyvinyl acetate cement PVAC paint was used as a paint composition. The calculations were carried out for the conditions of Moscow. A comparison is made of the stresses in the coating on a smooth and rough surface. I has been found that an increase in the relief angle of the substrate surface roughness does not cause a significant change in the magnitude of stresses. The stress concentration in the zone of contact between the coating and the rough surface of the cement substrate has been established. A diagram of the distribution of stresses in the PVAC coating is presented. It was revealed that at some distance from the zone of the microdepression of the substrate surface relief, an increase in stresses is observed, which, depending on the angle of inclination of the relief, are s х = (1.007-1.021) MPa. At the peak of the relief, the stress values in the contact zone are less and amount to 0.403-0.441 MPa. The influence of the substrate roughness has practically no effect on the values of normal stresses on the coating surface, which are 0.835-1.001 MPa. The probability of peeling off the coating is estimated. The possibility of peeling of the coating has been established, tk. stress values are less than the adhesion strength, which is 0.9-1.1 MPa. It is recommended that in order to increase the resistance of coatings to peeling, strive to create a uniformly distributed roughness of the substrate surface.

In this study, the authors consider sand pads, namely the production process and quality control. The main problem of using the compacting factor as a criterion for assessing the quality of sand pads is the impossibility of calculating future deformations of foundations, as well as the duration of laboratory studies to determine it. Thus, the development of a technological solution for the use of express methods for controlling the compaction of soil structures, which are based on empirical data and can reduce the economic costs of construction, is an urgent task. The direct object of the study is the sand pad under the production facility. In the process of installing a sand pad, layer-by-layer control of the degree of compaction was carried out according to the compacting factor with the determination of the maximum density according to the method of GOST 22733-2016, and the modulus of soil deformation according to selected soil samples for compression tests. For each layer, the compaction coefficient was determined at 5 points, the deformation modulus at 3 points. Additionally, tests were carried out using a dynamic density meter. The main result of the study is the construction of a calibration dependence of the constrained modulus on the dynamic modulus of elasticity of the soil based on the results of statistical processing. Based on the test results, it was found that the experimental data are equally accurate, the resulting model is adequate. The difference between the experimental data and the calibration dependence does not exceed 18 %, which is a good convergence for empirical methods. The obtained experimental dependence allows, with a sufficient degree of accuracy, to quickly control the quality of the sand pad.

The task of this research is to determine the values of the generalized strength parameters of the foundation soil and , at which the depth D Z of the development of Coulomb areas of plastic deformation under the edges of the foundation of finite rigidity thickness Н , loaded with a uniformly distributed load of variable intensity q and foundation of the same thickness, bearing a rigid above-foundation structure of variable height H * will correspond to the closure of plastic area under the base of the foundation what is complied with the ultimate state of the foundation (according to Prandtl). To carry out computer modeling a list of variables of design parameters that influence the process of formation and development of plastic areas under the sole of the foundation, and the intervals of their change, has been established. As a result of the calculations and processing of the data obtained it was found that the numerical values of and differ significantly from each other: equations of approximating curves of dependencies of the form have different forms correspondingly and are described by the different approximating expressions. If it is given the values of the generalized strength parameters of the foundation soil and , which the soil mass should have after its fixing, then using the graphs shown in Fig. 6-10 and the table it will be possible to conclude whether the limit state of the fixed soil base will be achieved under given loads. In other words, focusing on the numerical values of and , it is possible to determine the values , which must be obtained in the process of fixing the soil base so that the specified external load does not exceed the maximum permissible value.