The dissertation on competition of a scientific degree of the candidate of technical sciences on a specialty 05.24.01 - Geodesy, photogrammetry, and cartography. - Kyiv National University of Construction and Architecture, Ministry of Education and Science of Ukraine, Kyiv, 2021
The dissertation presents the author's approach to solving the scientific and applied problem of improving the methods of determining the accuracy of geodetic works in the operation of main gas pipelines. A conceptual approach to determine the accuracy of geodetic works in the operation of main gas pipelines by modeling the stress-strain state of structures. The assessment of high-risk areas on the main gas pipeline has been performed.
The joint work of the pipeline with the soil base is modeled, and the basic methods and theoretical bases of modeling the stress-strain state of the soil bases are determined, as well as the theory of the development of the soil base and pipeline movement in time. The results of the calculations made it possible to clearly trace the regularity of the gas pipeline displacement with the change of the layer and soil properties. Maximum deformations occur in areas where stress and deflection increase. Also, the control of the stress-strain state of the gas pipeline section at certain stages of construction showed that the partial removal of soil does not provide complete unloading of the pipeline in the soil mass.
The assessment of high-risk areas on the main gas pipeline has been performed - which is the main preparatory step to the calculation of environmental risk indicators and determination of the parameters of the stress-strain state of the main gas pipeline. This makes it possible to identify potentially dangerous sections of the main gas pipeline for technical and organizational measures to ensure accidents during the operation of the main gas pipeline.
A method for a comprehensive assessment of geological risk factors has been developed, which is the basis for determining the stress-strain state of the pipeline, which requires a differentiated approach to establishing the accuracy of geodetic works for each section of the pipeline and allows to approximation the probability of geological hazards on the pipeline.
A computational and mathematical model was developed, which made it possible to develop an effective method for solving a system of complex differential equations of any kind by boundary conditions to obtain the results of calculations of the characteristics of the stress-strain state of the pipeline. The developed method has advantages over other methods of determining the stress-strain state of gas pipelines in terms of simplicity and efficiency of application and allows to solve traditional issues of detecting violations on pipeline routes.
The technique is based on the transition from the stress-strain state to the accuracy of geodetic observations. The calculation of the periodicity of geodetic observations of gas pipeline deformations has been improved. The distance that should be between the marks is substantiated so that the results of geodetic observations could be used to analyze the static condition of the pipeline with appropriate accuracy, and the frequency of geodetic works.
This approach allows to identify, refute or confirm the nature of the influence of geological factors on the results of numerical modeling, which is used to calculate the accuracy of geodetic works, in relation to the detection and prevention of deformations of gas pipelines. This takes into account the stress-strain state of the studied system, namely the system "pipeline - soil base", which allows you to reasonably identify and refine models of the system.
In the event of an emergency, the system allows you to predict the consequences, make management decisions, thereby reducing response time and reduce damage from possible emergencies. The structural scheme of the system of geodetic monitoring of gas pipeline sections with the development of landslide processes is developed.
The modern practice of engineering and geodetic observations of deformation processes requires the detection of minimal absolute displacements, which increases the requirements for accuracy of measurements, and the practical implementation of accurate regime observations using the latest automated engineering and geodetic equipment (satellite navigation systems, unmanned aerial vehicles, and unmanned aerial vehicles). and computer technologies for operational processing of measurement results, geodetic monitoring, preparation of information, and engineering solutions. It is these issues related to the study and implementation of advanced technologies, became the subject of the dissertation.
Keywords: risk, gas pipeline, stress-strain state, main gas pipeline, geodetic works, geodetic accuracy, engineering-geodetic equipment.
