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In 2018, in the process of coal mining by the open method in Kuzbass, about 1.0 billion tons of coal-bearing rocks were destroyed and sent to dumps, more than 50% of which, by their physical characteristics, meet the requirements for road construction materials. But for their use in the construction of temporary technological roads and public roads, information is needed on changes in physical properties as a result of exposure to repeated freezing and thawing. Such information is also necessary in coal mining, because in our region, natural factors have a great influence on the stability of the benches and ledges of the open-pit mines, the rocks in their contour zone during the autumn and spring periods freeze at night, in daytime they partially or completely thaw, in most cases, with full water saturation. The paper presents the results of laboratory studies of changes in the propagation speeds of longitudinal ultrasonic waves in sandstone and aleurolite samples, the most common coal-bearing rocks Вестник Кузбасского государственного технического университета. 2019. No 5, с.59-63 Шаламанов В.А., Паначев И.А. Влияние многократного замораживания и оттаивания ... 60 of Kuzbass section fields, and the effects of water saturation and repeated freezing and thawing in water and in air on their strength properties. As a result of processing the experimental data, ratios of the strength parameters and propagation speeds of ultrasonic elastic longitudinal waves were established. Conclusions about the possibility of using the ultrasonic method to control the condition of benches and ledges of the open-pit mines and change their strength properties with water saturation and subsequent freezing and thawing are made. This question is studied insufficiently and requires further research in each geological-economic areas of Kuzbass.

EFFECT OF MULTIPLE FREEZING AND THAWING ON THE STRENGTH PROPERTIES OF COAL-BEARING ROCKS OF KUZBASS