Baynazov U. R. 1, Arzikulov G. P
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- Table 2. Numerical value of rock movement in the bunker
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2.Results
Graphical and mathematical calculations of the analysis of the operation of a 7.8-meter-high bunker are shown in the illustration below of the results of the stress force on the main belt (fig.3). As shown here, at the considered height, rocks are torn off the conveyor belt at a speed of 5 m/s and hit the hopper, which extinguishes the rate of fall of the transported rock and the force of its impact during free fall on the main belt. In the illustration, the stress strength is represented in different colors: the maximum impact voltage is indicated in red, the minimum impact voltage is indicated in blue. The point of maximum impact stress is considered a danger zone. Fig.3. The value of the maximum impact stress of the rock in the center of the belt Fig.4. The graph of stresses in the hopper over time at a drop height of 7.8 m. On the graph, the maximum voltage value is indicated in green, the average voltage value is blue, and the minimum value is red. According to this graph, the maximum voltage is reached at 2.275 seconds(fig.4, table 1). Table 1. Numerical values rock stress 7.8 m.
Fig.5. Movement of rock in the bunker The graph shows the changes in the movement of the rock over time. It shows the distance of movement of the rock with a length of 8.04 meters in the process of falling on the tape from the height of the bunker 7.8 m (fig.5, table 2). Table 2. Numerical value of rock movement in the bunker
Fig.6. Graph of the stress and movement of the rock on the belt from the hopper height of 7.8 m In the graph presented, the stress and distance of moving the rock to the tape from the height of the 7.8 m bunker is 8.04 meters, and the time is 2.275 seconds (fig.6, table 3). Table 3. Stresses and displacements of the 7.8 m high hopper
Calculate the movement of the rock with the center of its mass Mc from the height of the hopper to the tape to the center[10]. We obtain the equation of the product relative to the center of gravity. We get some center of gravity of the soil relative to point C. For a body of mass M with a center C, consider the following equation in accordance with Newton's second law (fig.7): ; (1) Fig.7. Calculation scheme According to the formula shown below, we consider that the rock moving to the bunker of the conveyor with the tape is affected by the tape. The following initial conditions are optimal for this equation: Select the center of the O system on the lower tape so that the center of gravity C lies on the OY axis. According to this: ; (2) Condition for speed components: ; (3) We integrate according to the conditions (1), (2) and (3): (4) Suppose that an object of mass M touches point D (at a distance from the Oy) and that the velocity of point D decreases (due to the shock absorber of the hopper): = Let's write down the equilibrium equation for the section D, A directed in the direction opposite to the velocity F = F * (𝜗) = k𝜗: = ; (5) For this equation, the optimal condition (2), according this: ; (6) : (7) speed of the point D . Integrate formula (5) according to conditions (6) and (7): ; (8) If then: + For the : y= equation of motion. Using the initial conditions, the following systems of equations are determined: (9) Here: ; ; = ; = The general equation of motion will look like this: (10) Equation (9) must have =0, for the rock to hit the belt: From this equation we find t* (t* is the touch time). From here we find the velocity and acceleration at the point of impact using t*. (11) Hence the corresponding values of the forces acting on the tape are equal to: (12) Conclusions We have studied and analyzed in detail the problems of the process of operation of the CFT during stripping operations of coal mines. As a result of the analysis, it was revealed: 1. The main problems of overburden transportation are caused by various reasons for the burst of the main line tape. In this regard, careful calculations were carried out on the basis of the "Ansys" program, which made it possible to identify one of the main problems of frequent gusts of the main belt conveyor during operation, due to both the structural and technical features of the main belt itself, and the impact force of the extracted rock from the loading and unloading bunker of the CFT. 2.In order to identify the causes of the identified problems, an analysis of the process of the CFT operation was carried out taking into account its technical parameters (the speed of the tape, the degree of hardness and the angle of incidence of the rock on the tape, as well as the height of the hopper from which the rock is discharged onto the tape (7.8 m) according to the "Ansys" program. The results of the calculations showed that one of the main problems is caused by the height of the operational bunker. 3.Determination of the optimal height of the operational hopper avoids frequent gusts of the main conveyor belt. An important role is played by the peculiarity of the loading and unloading hopper design itself. Based on the results of the analysis and their implementation into practice, it can be argued that determining the optimal height of the loading and unloading hopper allows you to extend the life of the conveyor belt and thereby reduce the frequency of repairs of this structure. References: Lagerev A.V., Tolkachev E.N., & Boslovyak P.V. (2018). Design and research of the conveyor with hanging ribbon. In Design and research of the conveyor with hanging ribbon [Проектирование и исследования конвейеров с подвесной грузонесущей лентой] (p. 303). Academician I.G. Petrovskii Bryansk State University. https://doi.org/10.5281/zenodo.1197308. 2. 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