Weakening of rock strength under the action of cyclic dynamic loads

• Main Authors: Valentyn Korobiichuk, Viktor Kravets, Ruslan Sobolevskyi, Anatolii Han, Viktoriia Vapnichna
• Format: Article
• Language: English
• Published: PC Technology Center 2018-04-01
• Series: Eastern-European Journal of Enterprise Technologies
• Subjects: natural stone; energy capacity of destruction; resistance to impact actions; dynamic loads; propagation of ultrasonic wave
• Online Access: http://journals.uran.ua/eejet/article/view/127847

We report results of experiment on the estimation of decreasing strength of natural stone exposed to repeated dynamic loading. The study was conducted in order to assess the feasibility of using natural stone for the accompanying extraction of stone blocks under conditions of gravel quarries. We examined samples from 13 Ukrainian deposits of natural stone. The stresses were created by a weight dropped on the tiles made of natural stone. The damage was evaluated using the ultrasonic device UK-14MP. The established resistance of rock to repeated impact actions showed that at a low specific energy of the impact (1.47‒2.7 kJ/m3) there are the granites (Zhezhelivski, Tokivski, Koretski deposits) that are almost not destroyed. These very deposits are suitable for the accompanying extraction of blocks of natural stone under conditions of gravel quarries. Building structures from these fields can be used in facilities and buildings that are exposed to vibration. Depending on the energy capacity of destruction, we conditionally divided natural stone into three groups. By applying a nondestructive control, we found that granites lose their strength prior to destruction from 11.6 to 41.5 % because of anthropogenic microcracking. The fatigue strength of granites is affected by the content of quartz; an increase in quartz results in increasing strength. It is demonstrated that the texture of granite exerts not a less impact on the strength of the stone; an increase in grain size in granite leads, despite a considerable content of quartz, to a decrease in the stone fatigue strength. Increasing accessorial minerals in granites leads to a decrease in fatigue strength