Construction and Geotechnics

The main provisions of the completion of final qualifying works (master's theses) by undergraduates studying in the field of training "Construction" at the Department of Bases and Foundations of the Kuban State Agrarian University named after I.T. Trubilin are given. The duration of the master's degree is two years for full-time and two and a half years for part-time studies. Undergraduates should start their final qualification work (FQW) two to three months after their enrollment in the master's program. The preparation of the FQW provides for the independent work of the undergraduate student on solving the tasks under the guidance of experienced teachers (professors, associate professors) or leading specialists in the construction industry. The general organization of work on the FQW is entrusted to the Dean's Office of the Faculty of Architecture and Civil Engineering and the graduating department. The topics of the FQW (master's theses) are determined by the graduating department, which can be adjusted after the master's student performs research work (RW) and passes pre-graduate practice at the last stage of training. At the same time, for undergraduates, there are varieties of FQW (research and design), the type of which is determined by the supervisor. The article presents the composition of the department that trains undergraduates, sample topics of the department's FQW and their structure, the procedure for appointing scientific supervisors (consultants). Undergraduates are trained according to the master's program: "Architectural design, reconstruction and geotechnical construction". The main stages of the implementation of the FQW, the timing, the results of the verification of the FQW for anti-plagiarism and the procedure of public protection are given.

This article is devoted to a detailed analysis of the stress-strain state of the soil mass of the bottom of the mine and the presentation of an approach to assessing the values of the physico-mechanical properties of the fixed soil of the base, ensuring its strength and water resistance. To analyze the stress-strain state, a computer program was used in which the finite element method was formalized to determine stresses and displacements, and the Coulomb plasticity condition was used to determine areas of plastic deformations (regions of the limit state). Preliminary calculations have shown that the areas of plastic deformations are located directly under the upper boundary of the bottom, developed mainly in the horizontal direction, with a shaft width of d = 5 m, their thickness is approximately 25 % greater than at d = 4 m. The intensity of vertical movements at d = 5 m is also slightly greater than at d = 4 m. The vertical coordinates of the points of the arch of the "lifting" of the bottom of the shaft are defined as the difference between the vertical movements of the points of its surface and the point of its contact with the sheet pile. The vertical displacements of this "common" point are the same, since the condition of complete adhesion is fulfilled at this point in the finite element calculation. To determine the properties of the soil of the bottom of the mine, which, after strengthening, should ensure its strength and water resistance, we will use a technique that allows us to ensure the fulfillment of conditions under which there are no zones of tensile vertical stresses and areas of plastic deformation in the bottom of the mine. Using the method of reverse calculation, the well-known formula of V.A. Florin and the concept of reduced connectivity pressure, it was possible to establish numerical values of the angle of internal friction and specific adhesion, which must be given to the soil of the interspun space in the process of fixing it, so that the conditions stipulated above are provided.

Galvanizing of welded seams is an effective method to prevent corrosion of building structures. As a rule, galvanic or electrolytic deposition of zinc coating on a metal surface for anti-corrosion protection is carried out at the factory using baths. Factory anti-corrosion coating is of high quality and durability. But in the conditions of a construction site, structures are assembled using welding, during which the factory anti-corrosion protection is destroyed. Therefore, it is necessary to provide additional high-quality anti-corrosion protection of assembly welds at the site of construction installation. Today, one of the most relevant materials for the protection of metal surfaces is zinc. Therefore, the article considers the possibility of using the galvanizing method for anticorrosive protection of field welds. On the basis of one of the patents, a mobile device was developed that makes it possible to perform anti-corrosion protection of assembly welds in the conditions of a construction site using the electrolytic method. The quality of the coating applied by the proposed device meets the requirements of regulatory documentation. Also, the article is a description of the testing of anti-corrosion coatings on metal samples with a welded seam, followed by a comparative analysis of methods for protecting field welds from corrosion: paint and varnish coatings for metal, galvanic zinc plating using the developed device; cold galvanizing. When conducting a comparative analysis of the types of anti-corrosion coatings, the method of galvanic or electrolytic zinc coating using the proposed mobile device turned out to be more effective than paint coatings and cold galvanizing based on a comparative analysis of types of anti-corrosion coatings. Also, the method of galvanic zinc coating is the most rational, since this method has a low consumption of zinc compared to other methods of galvanizing.

The main task in the development of road concrete is to increase the strength of concrete in bending, which will increase the service life of the coating up to 50 years. This can be facilitated by new types of cement concrete, for example, compacted concrete with a reduced modulus of elasticity in the foundations of highways. Rolled concrete with the lowest possible content of water and binder has the maximum degree of compaction of the material, while ensuring the formation of a dense structure. Such concretes can be obtained using damping anionic bituminous emulsions with certain properties. Careful selection of an emulsifier plays an important role in obtaining anionic bitumen emulsions with the required properties. When obtaining bitumen emulsions, special requirements are imposed on emulsifiers, since they largely determine the structure and properties of the bitumen emulsion. The mechanism of action of the emulsifier is to reduce the surface tension at the interface between the bitumen and water phases and to form a protective shell around the bitumen particles. The use of flotation tar is proposed as an initial product for the production of an anionic emulsifier. In this work: the optimal formulation and technology of combined emulsification for the preparation of a finely dispersed bitumen emulsion are determined; The main operational properties of road concretes modified with a finely dispersed anionic bitumen emulsion have been studied. It was revealed that the bitumen emulsion with 2 % flotation tar, obtained by the combined method, is more structured and has a smaller size of bituminous particles. It has been proven that, in terms of uniformity, the bitumen emulsion obtained by combined emulsification is 5 times better than the bitumen emulsion prepared in the traditional way. Modification of rigid concrete, developed with an anionic bitumen emulsion, made it possible to increase the compressive strength of concrete by 30 %, bending strength by 40 %, and increase frost resistance by 2 times. The optimal concentration of the modifying additive was also determined, which is 5 % of the anionic bitumen emulsion by weight of cement for rigid concrete mixtures.