ALGORITHM FOR DETECTING DEFECTS AT CONSTRUCTION OBJECTS

Статья посвящена разработке алгоритма раннего обнаружения дефектов на объектах строительства, применяемого в системах геотехнического мониторинга для повышения точности прогнозных оценок устойчивости сооружений. Не смотря на имеющиеся наработки в сфере геотехнического мониторинга и оценки устойчивости геотехнических систем, возникающие за проектные ситуации, которые приводят к возникновению аварий и катастроф техногенного и природного характера, показывают необходимость дальнейшего развития алгоритмического обеспечения систем геотехнического мониторинга. Приведена блок-схема алгоритма раннего обнаружения дефектов на объектах строительства, построенного на основе авторского подхода выделения ключевых точек геотехнического мониторинга, методов теории бифуркаций, а также нейросетевого анализа. Отличительной особенностью разработанного алгоритма кроме применения нейронной сети для подстройки под геотехнические особенности, является возможность динамической корректировки диапазонов варьирования пределов устойчивости геотехнической системы, заложенных в проектной документации на исследуемый объект строительства. В описаны результаты практического применения разработанного алгоритма в системе геотехнического мониторинга (наблюдения осуществлялись с 2016 по 2021 год) параметров грунтового основания, а также физико-механических параметров элементов конструкций фундамента и сооружения. В качестве сооружения выступало трехэтажное здание, возведенное на кирпичном ленточном фундаменте. Объект исследования находится в г. Муроме Владимирской области. В ходе применения разработанного алгоритма были получены оценки мест образования дефектов в контрольных точках и их локализация, которые были подтверждены в ходе дальнейших наблюдений. Разработанный алгоритм может применяться в системах геотехнического мониторинга на протяжении всего жизненного цикла геотехнической системы. The article is devoted to the development of an algorithm for early detection of defects at construction sites, which is used in geotechnical monitoring systems to improve the accuracy of predictive estimates of the stability of structures. The emerging design situations that lead to accidents and catastrophes of a man-made and natural nature show the need for further development of algorithmic support for geotechnical monitoring systems, despite the existing developments in the field of geotechnical monitoring and assessment of the stability of geotechnical systems. A flowchart of an algorithm for early detection of defects at construction sites is presented, based on the author's approach to identifying key points of geotechnical monitoring, methods of bifurcation theory, as well as neural network analysis. A distinctive feature of the developed algorithm, in addition to using a neural network to adjust to geotechnical features, is the possibility of dynamically adjusting the ranges of variation of the stability limits of the geotechnical system laid down in the design documentation for the construction object under study. The results of the practical application of the developed algorithm in the geotechnical monitoring system (observations were carried out from 2016 to 2021) of the parameters of the soil base, as well as the physical and mechanical parameters of the structural elements of the foundation and structure are described. The structure was a three-storey building erected on a brick ribbon foundation. The object of research is located in the city of Murom, Vladimir region. During the application of the developed algorithm, estimates of the places of defect formation at control points and their localization were obtained, which were confirmed during further observations. The developed algorithm can be used in geotechnical monitoring systems throughout the entire life cycle of a geotechnical system.

CONTROL OF THE FORMATION OF DESTRUCTIVE PRECESSES IN THE GEOTECHNICAL MONITORING SYSTEM

В данной статье предлагается алгоритм контроля образования деструктивных процессов в геотехнических системах. Предлагаемый алгоритм на практике корректирует диапазон допустимых параметров геотехнической системы на основе комплексной обработки данных о внешних факторов и комбинаций реакций системы, построенного на основе теории бифуркаций. По результатам работы алгоритма происходит формирование оценки изменения состояния геотехнической системы. В статье так же описаны результаты практического применения разработанного алгоритма на основе данных геотехнического мониторинга (наблюдения осуществлялись с 2016 по 2021 год)параметров грунтового основания, а также физико-механических параметров элементов конструкций фундамента и сооружения. В качестве сооружения выступало трехэтажное здание, возведенное на кирпичном ленточном фундаменте. Объект исследования находится в г. Муроме Владимирской области. В ходе применения разработанного алгоритма были выделены наиболее уязвимые ключевые точки геотехнической системы в которых развиваются скрытые деструктивные процессы. Полученные результаты также подтверждаются результатами моделирования в ЛИРА-САПР напряжений в конструкции фундамента здания при изменении долей природной влажности верхних слоев грунта. Таким образом, хотя в решении задач геотехнического мониторинга и оценки устойчивости геотехнических систем существуем множество подходов, тем не менее постоянно возникающие за проектные ситуации, приводящие к возникновению аварий и катастроф техногенного и природного характера, показывают их не высокую эффективность. Поэтому, применение разработанного алгоритма актуально при прогнозировании устойчивости геотехнической системы за счет коррекции в динамическом режиме допустимых пределов варьирования физико-механических параметров устойчивости геотехнической системы, полученных в проектных расчетах. This article proposes an algorithm for controlling the formation of destructive processes in geotechnical systems. In practice the proposed algorithm corrects the range of acceptable parameters of the geotechnical system based on complex data processing on external factors and combinations of reactions of the system. It built on the basis of the theory of bifurcations. Based on the results of the algorithm, an assessment of changes is formed in the state of the geotechnical system. The article also describes the results of the practical application of the developed algorithm based on geotechnical monitoring data (observations were carried out from 2016 to 2021) of the parameters of the soil base, as well as the physical and mechanical parameters of the structural elements of the foundation and structure. The structure was a three-story building erected on a brick ribbon foundation. The object of the research is located in the city of Murom, Vladimir region. During the application of the developed algorithm, the most vulnerable key points of the geotechnical system were identified in which hidden destructive processes develop. The obtained results are also confirmed by the results of modeling in LIRA-CAD of stresses in the structure of the foundation of a building with a change in the proportion of natural humidity of the upper layers of the soil. Thus, although there are many approaches to solving the problems of geotechnical monitoring and assessing the stability of geotechnical systems, nevertheless, constantly emerging project situations that lead to accidents and catastrophes of a man-made and natural nature show their low efficiency. Therefore, the application of the developed algorithm is relevant when predicting the stability of the geotechnical system due to the correction in the dynamic mode of the permissible limits of variation of the physical and mechanical parameters of the stability of the geotechnical system obtained in the design calculations.

Influence of a Thin Horizontal Weak Layer on the Mechanical Behaviour of Shallow Foundations Resting on Sand

The presence of minor details of the ground, including soil or rock masses, occurs more frequently than what is normally believed. Thin weak layers, shear bands, and slickensided surfaces can substantially affect the behaviour of foundations, as well as that of other geostructures. In fact, they can affect the failure mechanisms, the ultimate bearing capacity of footings, and the safety factor of the geotechnical system. In this research, numerically conducted through Finite Element Code Plaxis 2D, the influence of a horizontal thin weak layer on the mechanical behaviour of shallow footings was evaluated. The obtained results prove that the weak layer strongly influences both the failure mechanism and the ultimate bearing capacity if its depth is lower than two to four times the footing width. In fact, under these circumstances, the failure mechanisms are always mixtilinear in shape because the shear strains largely develop on the weak layer. However, the reduction in the ultimate bearing capacity is a function of the difference between the shear strength of the foundation soil and the layer. The presence of a thin weak layer decreases the ultimate bearing capacity up to 90%. In conclusion, this research suggests that particular attention must be paid during detailed ground investigations to find thin weak layers. Based on the obtained results, it is convenient to increase the soil volume investigation to a depth equal to four times the width of the foundation.

SIMULATION AND BIFURCATION ANALYSIS OF GEOTECHNICAL SYSTEM STABILITY UNDER VIBRATION

The automation of control processes for the stability of geotechnical systems is a great challenge involving the development of methods for multivariate analyzing and forecasting the stability with the subject to the nonlinearity of material stiffness parameters. The aim of the study is to improve the efficiency of automated control systems for geotechnical stability by developing an approach to detect negative changes in bifurcation diagrams of vibration displacement parameters of object structures. The authors present a mathematical model of the dynamic behavior of structural elements of an object as an elementary unit of a geotechnical system that describes a response to an external vibration action. An algorithm of bifurcation analysis is presented, which allows authors to determine the initial transition stage of the object structure to an unstable state by the acceleration values of forced oscillations exceeding the model parameters. A bifurcation diagram of stability changes in the structure of object at the displacement resulting from the load increase under vibration action has been constructed. This diagram, which type of codimension-one bifurcations is merging, enabled to determine the critical load values resulting in an unstable state transition of a system due to the influence of a combination of vibration factors. The efficiency evaluation of the proposed approach was carried out by the comparison with the results of construction stability calculations obtained by the use of the dynamic coefficient. The difference between the values of the maximum object displacement without loss of the stability under vibration action, obtained by the standard calculation method and using the developed model, is 32.5%, and it is significant in the theory of structure stability. When exogenous vibration noise is used as a source of a sounding signal, the application of the developed approach in automated control systems for geotechnical stability enable to change the permissible stability thresholds of objects being exploited depending on the level and combination of influencing factors.

Information processing of river water level dynamics during monitoring of geotechnical system stability

Introduction. During the operation of urban and rural geotechnical systems, the mechanical indicators of the stability of the soil base are significantly influenced by the regime and dynamics of the physicochemical properties of nearby water bodies, caused by the development of karst-suffusion processes. The results of information analysis of data on the dynamics of the river runoff level and water salinity make it possible to increase the accuracy of predictive estimates of the loss of stability of the geotechnical system due to the development of karst-suffusion processes. Goals and objectives. The aim of the work is to improve the safety of operation of geotechnical systems and increase the efficiency of modeling and forecasting systems for geodynamics by developing an algorithm for assessing changes in the risk of developing suffusion processes based on an analysis of the dynamics of the level of groundwater and surface waters. Methods. The paper analyzes the data on the number of karst sinkholes depending on the dynamics of the river water level, obtained on the basis of statistical sources and reports on regime observations, as well as a result of field research. In the course of data processing, a spline interpolation method was used, an algorithm and a neural network for predicting a failure using the Bayesian regularization method based on a network training function was developed, which updates the weight and bias of the value in accordance with the Levenberg-Marquardt optimization. Results and its discussion. Based on the results of practical use, the effectiveness of the developed algorithm was confirmed in identifying the dynamics of the formation of dips during information processing of data on changes in the water level in the Oka River and data on the appearance of new dips in the period from 2012 to 2019. Conclusion. The results obtained in the work make it possible to judge the presence of the expediency of using the developed algorithm for assessing the occurrence of karst sinkholes when monitoring the stability of geotechnical systems and assessing the safety of their operation in general. Prospects for further work are associated with expanding the set of training data and adapting the structure of the neural network to the individual characteristics of the territories by introducing additional geological, hydrological and climatic parameters into the processing. Key words: geotechnical system, stability, karst sinkhole, bifurcation parameters, information processing of data.

Substantiation of fuzzy logic algorithms for control problems of a geotechnical systems

The article presents results of study of intelligent fuzzy logic algorithms developed on the basis of fuzzy logic methods for information system of the mine safety system. In order to prevent emergency situations caused by the lost geotechnical system stability due to the uncertain behavior of the rock mass, a new fuzzy controller was designed which could generate an additional control signal. For the fuzzy controller, methods of data fuzziness, inference and de-fuzziness were validate, and linguistic rules were designed in order to control parameters of the geotechnical system. With the help of the Cauchy problem solved by Runge-Kutta method of the 4th order, designed a software model of the proposed system which simulated the system operation. The model has proved operability and static stability of the developed algorithms. Output signal of the fuzzy controller can be used as information for estimating risk for geotechnical systems, preventing possible emergency situations and, consequently, can improve job safety in the mines.

Sustainable model for the implementation of a green building project

The problem of today is a complex study of the multicomponent geotechnical system of large green building projects. The essence of the green building project is to introduce a set of technologies to improve the construction process and minimize future costs. A comprehensive implementation of energy-efficient technologies considered by the author allows obtaining an overall reduction in heat consumption from 30% to 70%, depending on the list of measures and selected technical solutions, as well as on the initial technical condition of the house. Based on these calculations, during the period under consideration, the NPV indicator is positive, and as a result, the proposed project pays off. The payback period of the Energy Efficient Home project is within 10,29 years, and the project is quite efficient. Taking into account the research data, it is planned to develop an algorithm for assessing the geomonitoring of environmental impacts in the development of green building projects.