The influence of high temperatures on limestone P-wave velocity and Schmidt hammer strength

2006 ◽  
Vol 43 (6) ◽  
pp. 980-986 ◽  
Author(s):  
Ö. Kılıç
Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7612
Author(s):  
Haitham M. Ahmed ◽  
Hussin A. M. Ahmed ◽  
Sefiu O. Adewuyi

Rocks’ physical, mechanical, and mineralogical properties are essential in the design process of underground applications. To understand changes in these rocks’ properties at high temperatures, numerous studies have been conducted on several rock types, with little being known about microschist rock. This paper presents experimental study on the physical (e.g., density and P-wave velocity), mechanical (uniaxial compressive strength (UCS)), and microstructural behavior of microschist rock at room temperature (22 °C) and at high temperatures, i.e., 400, 600, and 800 °C. The results indicated that as the temperature increases, the microschist’s color changed, and dry density decreased by 0.97% at 800 °C. Additionally, the average P-wave velocity of microschist decreased by 4.14, 7.07, and 34.23%, at 400, 600, and 800 °C, respectively. Similarly, at these temperatures, the UCS of the microschist decreased by 34.4, 56.9, and 80.1%, respectively. Further findings from microscopic studies reveal that the observed changes in physical and mechanical properties were due to the structural deformation of the microschist at high temperatures.


2021 ◽  
Author(s):  
Dariusz Chlebowski ◽  
Zbigniew Burtan

AbstractA variety of geophysical methods and analytical modeling are applied to determine the rockburst hazard in Polish coal mines. In particularly unfavorable local conditions, seismic profiling, active/passive seismic tomography, as well as analytical state of stress calculating methods are recommended. They are helpful in verifying the reliability of rockburst hazard forecasts. In the article, the combined analysis of the state of stress determined by active seismic tomography and analytical modeling was conducted taking into account the relationship between the location of stress concentration zones and the level of rockburst hazard. A longwall panel in the coal seam 501 at a depth of ca.700 m in one of the hard coal mines operating in the Upper Silesian Coal Basin was a subject of the analysis. The seismic tomography was applied for the reconstruction of P-wave velocity fields. The analytical modeling was used to calculate the vertical stress states basing on classical solutions offered by rock mechanics. The variability of the P-wave velocity field and location of seismic anomaly in the coal seam in relation to the calculated vertical stress field arising in the mined coal seam served to assess of rockburst hazard. The applied methods partially proved their adequacy in practical applications, providing valuable information on the design and performance of mining operations.


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