Study on Impact Damage and Energy Dissipation of Coal Rock Exposed to High Temperatures

Abstract EN

The dynamic failure characteristics of coal rock exposed to high temperatures were studied by using a split Hopkinson pressure bar (SHPB) system.

The relationship between energy and time history under different temperature conditions was obtained.

The energy evolution and the failure modes of specimens were analyzed.

Results are as follows: during the test, more than 60% of the incident energy was not involved in the breaking of the sample, while it was reflected back.

With the increase of temperature, the reflected energy increased continuously; transmitted and absorbed energy showed an opposite variation.

At the temperature of 25 to 100°C, the absorbed energy was less than that transmitted, while this phenomenon was opposite after 100°C.

The values of specific energy absorption (SEA) were distributed at 0.04 to 0.1 J·cm−3, and its evolution with temperature could be divided into four different stages.

Under different temperature conditions, the failure modes and the broken blocks of the samples were obviously different, combining with the variation of microstructure characteristics of coal at high temperatures; the physical mechanism of damage and failure patterns of coal rock are explained from the viewpoint of energy.