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Angular measurement errors in underground mine surveying reference networks
(Державний університет "Житомирська політехніка", 2024) Nazarenko, V. O.; Brui, H. V.; Krivoruchko, А. O.; Levytskyi, V. H.; Назаренко, В. О.; Бруй, Г. В.; Криворучко, А. О.; Левицький, В. Г.
Surveyorʼs reference networks are the main geometric basis of all underground surveys and consist of polygonometric courses laid, as a rule, along capital and main mine workings. When laying polygons along mine workings, horizontal angles between each two adjacent sides of the course, inclination angles and lengths of the course sides are measured. Each measurement is performed with some error, which eventually leads to errors in determining the coordinates of polygon points. The peculiarities of underground polygonometric courses due to their forced configuration determined by mine workings, the presence of forced short sides and a limited number of starting points, contribute to the rapid accumulation of errors in the course as the distance from the starting points. The accuracy of measurements in the polygonometric passes, laid in the construction of underground reference networks, is characterized by the general normative indicators: the mean square error of measurement of horizontal angles of 20", vertical angles – 30". According to the requirements of the current normative instructions, the measurement of angles in underground polygonometric passages should be made with theodolites of T15 type or theodolites with the accuracy of the reference device not less than 15". The last requirement applies to theodolites of T30 type. In polygonometric moves laid along the mine workings with an angle of inclination of less than 30 °, the angles are measured in one repetition or reception. Measurement of angles in mine workings with an inclination angle of more than 30 ° is recommended to perform a method of techniques (at least two), observing the following rule: before each technique set the vertical axis of rotation of the theodolite in a plumb position and re-centering the device. If we proceed only from the instrumental component of the total error of angle measurement to ensure the mean square error of horizontal angle measurement ±20" theodolite type T15 should perform angle measurement in one full method, and theodolite T30 – in three methods. Instrumental error of angle measurement is caused by errors of sighting, counting, eccentricity of the limb and alidade, incorrect geometry of the horizontal circle, non-verticality of the theodolite rotation axis. The studies of errors in measuring horizontal angles in underground surveyorʼs polygonometric courses made it possible to draw the following conclusions: – the recommendations of the instruction «Surveying work at coal mines and surface mines» on the use of theodolites with a readout accuracy of 15" does not provide the required accuracy of horizontal angle measurements; – when using theodolites of T15 type to measure the angle with sides up to 20 m it is necessary to use only automatic centering of theodolite and signals; The scientific paper contains charts for determining the ways of centering and the number of methods of measuring horizontal angles in underground surveyorʼs polygonometric moves.
Determination of design indicators of earth surface deformations for mineable buildings and structures
(Інститут геотехнічної механіки ім. М.С. Полякова НАН України, 2023) Nazarenko, V. O.; Brui, H. V.; Kuchin, O. S.; Назаренко, В. О.; Бруй, Г. В.; Кучин, О. С.
Coal is one of the main sources of energy in Ukraine. Underground coal mining is concentrated in the ar-eas of Eastern and Central Donbas, Western Donbas, and in the Lviv-Volyn region. Development of coal seams leads to displacement of rocks and uneven subsidence of the surface. Surface movements and deformations cause serious damage to the environment. They affect residential and industrial infrastructure, and can cause destruction or disruption of operating conditions. Risks to surface structures can be reduced by predicting subsidence and surface deformation over underground workings. In Ukraine, the method of typical subsidence and deformation distribution functions is used for forecasting. This is a simple and universal method, but it does not take into account the differences in deformations in different zones of the shear trough depending on the direction of movement of the face. For this reason, incorrect predic-tive estimates of the impact of mining operations on the earth's surface, man-made natural, industrial and civilian objects arise. This paper presents a methodology for determining the estimated deformations of the foundations of civilian build-ings that are being faked, taking into account the assessment of the estimated impact of mining operations, which takes into account the peculiarities of the formation of the shear trough in space and time. This methodology was developed to supplement and clarify the "Temporary technical conditions for the protection of structures and natural objects from the impact of underground mining operations. KD 12.00159226.013-95" for the conditions of underground mining of coal seams in the Western Donbas, as well as other deposits with similar conditions and parameters of the earth surface displacement process. It is based on modern concepts of rock and earth surface movements during underground mining of coal seams with horizontal and gentle rock occurrence; results of analysis of numerous instrumental surveying obser-vations, including frequency ones, at observation stations of mines in Western Donbas. The obtained regularities allow for a more objective selection and application of protection measures for civil buildings. This reduces the risks during the operation of buildings, makes it possible to plan repair and restoration work, and to make a rea-sonable assessment of buildings and territories in the real estate market.