ROLLING MOTION OF THE PONTOONS IN SUMPS OF OPEN-PIT COAL MINES IN KUZBASS (ARTICLES REVIEW. CONTINUATION)
Open pit mining requires sump pumping for groundwater control. In order to prevent flooding of coal faces it is necessary to regularly pump out the water coming to the drain sumps. For this purpose the water removal-plants in the form of the pontoons with pumping equipment on it are used. The recommendations to use the pontoons in open pit coal mines are still not elaborated. Thus, in the authors’opinion, the issue of the pontoons safe use is urgent. Over recent years articles devoted to various aspects of the pontoons use (buoyancy, stability rolling motions) have been written. The issues of the pontoons buoyancy and stability have been summarized. Presented article gives a review of works discussing the problem of rolling motion of the pontoons and its dynamic stability. The principal types of the pontoons motions are heaving, rolling and pitching. It is noted that the reasons for the rolling can be both external forces, capable of removing the pontoon, and the regular waves that appeared on the liquid surface. In the first case, the rolling occures on «still water» and corresponds to free motions of the pontoon, which diminish with time.In the second case, the rolling motion is forced, since it is caused by periodically changing pressure forces arising when the water level in the tube-floats of the pontoons is raised and lowered. The pontoon can execute parametric oscillating motions both in the longitudinal direction and in the transverse direction due to intermittent dipping and floating of the pontoon on the disturbed surface of liquid.Regularities between the parameters characterizing the parametric rolling of pontoons are noted, and the regions of its instability are indicated.
Keywords: DRAIN SUMPS OF OPEN-PIT COAL MINES, PONTOONS, WATERLINE, METACENTRIC HEIGHT, ADDED-LIQUID MASS, WAVE FREQUENCY, PONTOONS TOSSING ON STILL WATER, PONTOONS TOSSING ON REGULAR WAVES.
Imprint: Cherdantsev S.V., Cherdantsev N.V. Rolling motion of the pontoons in sumps of open-pit coal mines in Kuzbass (Articles review. Continuation). Bulletin of Scientific Centre VostNII for Industrial and Environmental Safety. 2018. № 4. pp. 39-55.
Авторы: S.V. Cherdantsev, N.V. Cherdantsev
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