Investigating the correlations between point load strength index, uniaxial compressive strength and Brazilian tensile strength of sandstones. A case study of QwaQwa sandstone deposit

2021 ◽  
Vol 12 (1) ◽  
pp. 67
Author(s):  
Peter Kolapo ◽  
Prosper Munemo
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Uniaxial Compressive Strength ◽  
Point Load ◽  
Strength Index ◽  
Brazilian Tensile Strength ◽  
Point Load Strength ◽  
Point Load Strength Index

scholarly journals Experimental Study on Mudstone’s Strength Characteristics in Deep-Buried Coal-Measure Formation: A Case Study of Permian Longtan Formation

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Ke Li ◽  
Weijian Yu ◽  
Youlin Xu ◽  
Long Lai ◽  
Hui Zhang ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Uniaxial Compressive Strength ◽  
Rock Mechanics ◽  
Point Load ◽  
Strength Characteristics ◽  
Coal Measure ◽  
Strength Index ◽  
Point Load Strength ◽  
Point Load Strength Index ◽  
Linear Fitting

To investigate the strength characteristics of mudstone in deep-buried coal-measure formation, four types of experiments have been conducted: (i) the X-ray diffraction (XRD) test; (ii) the scanning electron microscope (SEM) scanning test; (iii) the point load strength index test; and (iv) the uniaxial compressive strength test. It was concluded that the mudstone of the deep-buried coal measures in the Longtan Formation is dominated by chlorite, quartz, and albite using the XRD test, of which chlorite is primary, accounting for 74.3%. It was found that the three minerals in the mudstone are unevenly distributed using the SEM scanning test, albite is irregularly distributed in chlorite, and quartz is present in the albite and chlorite. Sixty-five specimens were tested for the point load strength index. After processing the data using the method suggested by the International Society for Rock Mechanics and Rock Engineering(ISRM), it was found that the maximum value of Is(50) was 6.10 MPa, the minimum is 0.14 MPa, and 53% of the specimens’ Is(50) values are below 2.0 MPa. The RMT-150C rock mechanics testing machine was used to conduct uniaxial compression tests on six specimens. The maximum uniaxial compressive strength (UCS) value is 59.26 MPa, the minimum value is 31.77 MPa, and the average is 45.64 MPa. Linear fitting and logarithmic fitting are carried out for the correlation between UCS and Is(50). The goodness of fit R2 of the linear fitting is 0.863, and that of the logarithmic fitting is 0.919, indicating a strong correlation between them. When it is challenging to make standard specimens, Is (50) can be used to estimate UCS.

scholarly journals PHYSICAL PARAMETERS, TENSILE AND COMPRESSIVE STRENGTH OF DOLOMITE ROCK SAMPLES: INFLUENCE OF GRAIN SIZE

2020 ◽  
Vol 26 (8) ◽  
pp. 789-799
Author(s):  
Ali Lakirouhani ◽  
Farhad Asemi ◽  
Afshin Zohdi ◽  
Jurgis Medzvieckas ◽  
Romualdas Kliukas
Keyword(s):  
Grain Size ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Mineral Composition ◽  
Uniaxial Compressive Strength ◽  
Wave Velocity ◽  
Strong Correlation ◽  
Point Load ◽  
Brazilian Tensile Strength ◽  
Point Load Strength

The purpose of this paper is to investigate the strength, physical and engineering index parameters of selected dolomitic rocks with emphasis on grain size. For this purpose, three groups of dolomite from north western Iran, with the same mineral composition but different grain size, were selected; fine grain, medium grain and coarse grain. Three sets of laboratory experiments are performed on 32 samples: first; petrography tests for determining mineral composition and their percentage, and microstructure of rock containing grain size and grain size distribution, second; experiments to determine the physical properties of the rocks included density, compressional and shear wave velocity, and the third category of experiments included uniaxial compressive strength test, Brazilian tensile strength and point load strength. According to the results; there are significant positive correlation between grain size and uniaxial compressive strength (r = 0.89), point load strength (r = 0.58), Brazilian strength (r = 0.69), and average Young’s modulus (r = 0.64). Also, with increasing grain size, density decreases (r = –0.77). There is strong correlation between compressional wave velocity and shear velocity (r = 0.88). There are also a strong correlation among the uniaxial compressive strength, Brazilian tensile strength and point load strength.

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