Introduction. The subject of the study is a type of retaining structure representing a series of blocks filled with crushed stone which are installed on top of one another without a rigid connection. The relevance of the study is set by the necessity of developing a design justification of the considered retaining wall constructive solution under various operating conditions. The scientific novelty of the study consists in justification and development of new technical solutions aimed at expanding the scope of application for promising retaining structure designs, whereas the practical significance of the study consists in development and refinement of construction technologies related to such designs.

Materials and methods. Normative methods and recommendations are used for inspection and systematization of information on the technical condition of erected retaining structures. Visual inspection of the structures with photo fixation of damages and defects, measurement works, as well as geodetic works with fixation of coordinates of characteristic points of retaining structures were carried out. Methods of analyzing the stress-strain state of the structure allowed to develop new technical solutions in terms of involving the surrounding soil in the work of the structure.

Results. The analysis of the results of the survey of retaining structures carried out at the Vladivostok city objects since 2010 has shown that the categories of technical condition of the surveyed objects are defined as normative and serviceable. In order to expand the scope of application of the structures under consideration in terms of the range of characteristics of the retained soil and increase the height of the retaining wall, new technical solutions were developed aimed at increasing the massiveness of the wall and involving the retained soil in ensuring the operational qualities of the retaining structure.

Conclusions. As a result of the research, for the first time the information on the technical condition of the operated retaining structures made of soil-filled box blocks was systematized: in general, the walls show good serviceability in rather severe conditions of the Far East of Russia. The developed new technical solutions will make it possible to reasonably expand the application area of the considered structures due to the combination of positive qualities of semi-gravity retaining wall structures and reinforced soil technologies.

Introduction. One of the most unfavourable factors affecting building structures during their operation is moisture, which, if materials are incorrectly selected, can condense both in the thickness and on the inner surface of the fence. To prevent moisture condensation on the surface of the enclosing structure, the following condition must be fulfilled: the temperature of the inner surface of the enclosure must not be lower than the dew point temperature of the internal air. To avoid the above problems, it is necessary to carry out thermal engineering calculations of building structures with the greatest accuracy at the design stage.

Materials and methods. An analytical study of flat temperature fields in the thickness of a heterogeneous insulated external wall with a monolithic reinforced concrete frame was carried out using the method developed by K.F. Fokin. The calculation of plane temperature fields comes down to determining the temperature in each node of the enclosing structure. To do this, the wall structure was divided into nodes by a coordinate grid, then equations were compiled by which the above-mentioned values were determined and summarized in tabular form. Exact calculations were carried out by the method of integration (successive approximation) and stopped at the approximation in which the temperatures in each of the nodes did not differ from the temperatures of the previous approximation by more than 0.1 °C.

Results. To achieve the required result, eleven approximations were performed. Based on the calculated values, the heat transfer coefficient of the enclosure under study was determined. An analysis of the results obtained using the method of calculating flat temperature fields relative to the previously accepted values was carried out. The discrepancies between the values of previously accepted temperatures and the calculated values are determined.

Conclusions. After carrying out these calculations, it was revealed that the use of the temperature field method to calculate the heat transfer coefficient of a non-uniform structure is justified if the greatest calculation accuracy is required. To determine temperatures within the structure, especially in places of greatest heterogeneity, the temperature field method should be used, since it significantly increases the accuracy of the calculation.

Introduction. The literature review of research in the field of dynamic calculation of composite structures is carried out, which shows that research in the field of damping of dynamic impacts on coatings of buried structures is actual. At the same time, the issues of asymmetric impulse impacts remain insufficiently studied.

Materials and methods. A typical structural solution of a pavement slab of a buried structure subjected to impulse loading is considered. The deformation is modelled in the volumetric formulation by the finite element method. The dynamic effect is represented as a set of scaled time functions. This type of modelling allows the variable impact point and the change in impact intensity to be taken into account. The physical non-linearity of the materials is taken into account based on plasticity models of the fibre concrete and reinforcement. The JWL model was used to determine the initial load moment.

Results. Limits of dynamic load corresponding to the pre-failure state of the structure were determined. The thickness of the pipes used as damping inserts in the support nodes was varied. A series of calculations were carried out with different thicknesses of damping (crumpled) inserts under asymmetric impulse loading. The equivalent stresses according to the energy theory of strength were considered as time-observed parameters for symmetrical reinforcement of the transom parts of the slab. A comparison was made with previous studies dedicated to the calculation of the slab for symmetrical impacts.

Conclusions. The high efficiency of the use of damping inserts was established, and the highest value of the dynamic ultimate load in comparison with a rigid bearing unit and a solid pipe was obtained with the thickness of the inserts equal to 9 mm. Prospects and further research directions are defined.

Introduction. When developing territories with certain engineering and geological specificity, a number of foundation construction issues remain unresolved. Such specificity is caused by the combination of different regional parameters of the territories under consideration, which necessitates the development of existing methods of calculation and design of foundations for multi-storey and high-rise buildings.

Materials and methods. The authors carried out the work on generalization of engineering-geological conditions of more than 100 construction sites in the south of Russia, which are characterized as complex according to the current regulations (CP 47.13330.2016). It was found that the existing classification of complexity of engineering-geological conditions of construction does not always reflect the real conditions of development of such areas and needs improvement.

Results. The category of complexity of engineering-geological conditions is proposed — especially complex. The category of especially complex is understood as a combination of three or more factors: high design seismicity of the construction site; irregular alternation of foundation layers with their significant heterogeneity in terms of soil properties in plan and depth; risk of landslide and gravitational processes development; significant difference of relief marks within the construction site; relief slopes in two directions.

Conclusions. Taking into account the proposed category of engineering-geological conditions, the classification of methods of calculation and design of foundations of multi-storey buildings in especially complex conditions of construction has been developed and their practical implementation is presented. The particularly complex category of engineering-geological conditions of construction can be considered as promising for introduction into the normative documents.

Introduction. The issues of carrying out repair work on the reconstruction of pressure water pipelines using trenchless technologies “Arm-Pipe” and “Pipe-Arm”, which allow to ensure resource conservation during water transportation, are considered. Information on regulatory and technical documentation, conditions and installation procedure for protective coatings of the pipeline being restored, as well as well as the results of computational and analytical studies on comparative analysis and assessment of the possibility of reducing energy consumption during water transportation during the operation of the pipeline after its reconstruction are presented. The technologies of trenchless reconstruction of “Arm-Pipe” and “Pipe-Arm” for the rapid restoration of pressure pipeline networks, as well as issues of saving electricity when transporting water through pipelines after work on their reconstruction with these technologies are presented.

Materials and methods. Analytical as well as computational methods by using an automated software package to determine energy savings due to the reconstruction of dilapidated existing pressure pipelines using “Arm-Pipe” and “Pipe-Arm” technologies were applied.

Results. Calculations have revealed the advantage of “Arm-Pipe” technology in comparison with “Pipe-Arm” in terms of potential energy savings when transporting water through pressure pipelines.

Conclusions. A comprehensive analysis of the technical and energy potential of the implementation of advanced trenchless technologies for the reconstruction of dilapidated “Arm-Pipe” and “Pipe-Arm” pipelines was carried out.

Introduction. One of the main technogenic factors in the formation of environmental problems is the road transport complex, which has an aggressive impact on the environment. This is due to the high rates of urbanisation around the world. One of the main environmental risks in the process of rapid urban development is considered to be a change in the acoustic environment of urban streets due to an increase in noise pollution. It is necessary to identify and systematise the factors affecting the acoustic environment of public spaces of city streets, in order to subsequently identify patterns between the structure of streets, their functional and object content and the soundscape. The purpose of the study is to identify and systematize the main factors determining the noise impact on public spaces of urban streets, the quality of the acoustic environment of street territories.

Materials and methods. In the course of this study, the following methods were used: graphoanalytic, review, systematisation, comparative analysis and synthesis based on scientific and literary sources related to modern approaches to the assessment and organisation of the acoustic environment of urban spaces, as well as well as methods of protection from traffic noise.

Results. The main factors influencing the acoustic environment of the street space are identified, as well as determining the potential for changes to improve the soundscape. The factors of the acoustic environment are systematised into the following groups: noise factors — affect the noise level, the nature of its occurrence, propagation in the environment and its reduction; sound factors — influence the perception of the acoustic environment, as well as well as the quality of the soundscape of a city street.

Conclusions. Within the framework of this study, based on the analysis of modern domestic and foreign sources, which reflect approaches to the assessment, design of soundscapes, protection from noise of urbanised territories, an assumption is formulated about the relationship of noise and sound factors affecting the quality of the acoustic environment, which confirms the need for additional research of this dependence and the formation of a new strategy for the organization of the soundscape public spaces of city streets.

Introduction. One of foundations for the sustainable development and improvement of centralized water supply networks (CWN) and sanitation is the use of artificial intelligence (AI) based on machine learning (ML) algorithms and models: supervised, unsupervised, reinforcement learning. Leaks and unauthorized connections to CWN pose risks, leading to losses of drinking water and reduced pricing in the field of water resource metering. The relevance is associated with solving practical AI problems based on the latest innovations — forecasting and preventing accidents at CWN with optimal planning of repair work and timely maintenance. The purpose of study is to substantiate the role of AI using ML tools in the tasks of predicting pipeline failures and emergency situations in CWN.

Materials and methods. The study of information on the role of AI in preventing water leaks from water supply networks was carried out using the method of literature review of the used AI algorithms for predicting pipe failures in CWN.

Results. The ML models used for diagnostic analysis to predict water leaks from CWN are identified and presented. The review of technologies shows the use of 18 ML algorithms to solve problems related to leaks in CWN. Start of use of Kohonen neural network algorithms (KNN) in Russia indicates the availability of the only neural network software translated into Russian, STATISTICA Automated Neural Networks. Acoustic and ultrasonic methods for monitoring the condition of underground pipeline networks, based on the propagation of volumetric and directional waves (noise), are beginning to develop rapidly.

Conclusions. Among the conclusions — for the Sustainable Development of CWN, water utilities need to ensure reliable and continuous data collection, this is a key practice that will help make reliable decisions based on AI predictions after the ML phase. Databases may include: pipe diameter, length of the section and age of the pipe, pressure, type of soil. The pressure itself (or difference) in the network is not a sign of an accident. This parameter should be considered together with the number of network failures (accidents) in the sections.

Introduction. Modern methods of application of membrane technologies in industrial wastewater treatment are considered. The problem of reducing the negative impact on the environment by increasing the efficiency of treatment facilities is the most urgent at the moment. Recently, membrane technologies of wastewater treatment are becoming more and more demanded for their inclusion in the existing technological schemes of industrial enterprises located all over the world.

Materials and methods. Examples of technologies used in the dairy industry, oil and fat industry, automobile manufacturing, electric power industry, and tanning industry were studied. Domestic and foreign sources were analyzed.

Results. As a result of the work carried out, preference is given to technological schemes that allow to create waste-free production, namely, the reuse of treated water in the technological processes of the enterprise, which contributes to improving the efficiency of treatment facilities. The application of membrane technologies makes it possible to achieve the goals set to reduce the negative impact on the environment, but at the same time this technology is not without disadvantages.

Conclusions. The technology strongly depends on the specific composition of wastewater and the existing technological scheme of treatment. However, based on the reviewed examples in various industries, this technology is becoming more and more widespread and shows excellent results in reducing the negative impact of industrial effluents. The technology of membrane filters for creation of waste-free production should be further considered and developed.

Introduction. Characteristic features of the modern level of construction production are the increasing number of high-rise, large-span and unique buildings and structures, the increasing complexity of design solutions, the need for construction of objects in dense urban areas. On the example of a number of accidents that occurred at construction sites in Russia and other countries, the author presents the justification of the necessity to equip more and more construction sites with stationary systems for monitoring of load-bearing structures. The description of functional capabilities of these systems is given. The approaches to the construction of the system of automated assessment of the technical condition of building structures based on the information received from sensors are considered. The results of the analysis of monitoring systems designed according to two schemes of construction are presented, the features of the systems designed according to the concentrated and distributed schemes are defined. The results of the analysis of two monitoring techniques used in engineering practice — the technique of controlling the parameters of stress-strain state of bearing structure elements in the most loaded zones of the elements and the technique of controlling the integral characteristics of bearing structures under load — are shown. The peculiarities of each technique are presented.

Materials and methods. Theoretical research methods: review and analysis of Russian regulatory documentation, domestic and foreign engineering practice in the field of development of stationary monitoring systems for load-bearing structures functioning in real time.

Results. The current regulatory documentation and practical solutions in the sphere of development of stationary monitoring systems for load-bearing structures are considered. The results of the analysis of design schemes and monitoring methods are given.

Conclusions. The practical application of the design approaches outlined in this study enables the creation of effectively functioning monitoring systems for load-bearing structures.