Studies on Uniaxial Compressive Strength, Uniaxial Tensile Strength, Youngs Modulus, Poissons Ratio of Iron Ore in relation their Influence in Optimum Rock Blasting Process.Central Afghanistan

2019 ◽  
Vol 7 (4) ◽  
pp. 140-151
Author(s):  
Fatima Rezaye ◽  
Shivanna .
1979 ◽  
Vol 101 (2) ◽  
pp. 139-147 ◽  
Author(s):  
Hideo Awaji ◽  
Sennosuke Sato

A new approach of diametral compressive testing with circular anvils is proposed. The circular anvils are used to select a suitable contact width or to avoid the collapse of the specimen in the contact edge. Furthermore, the statistical corrections on the diametral compressive strength for the effects of the size and stress distribution are explained by the application of Weibull’s statistical theory. The experimental results of the diametral compressive testing are compared with the uniaxial tensile strengths for some kinds of graphite and marble, and the discrepancies between the two strengths are discussed. According to our macroscopic brittle fracture criterion under biaxial stress state, which was proposed recently, the tensile strength can be deduced from the diametral compressive strength σHC* and the uniaxial compressive strength σC as follows, σt*=KICKIIC12σCσHC*(1+σx/σH)+σC{σHC*(1−σx/σH)−σC}+σC2 where σt* is the deduced tensile strength, σx/σH is the ratio of maximum and minimum principal stresses at the center of the disk, and KIC and KIIC are the values of Mode I and Mode II fracture toughness. The deduced values σt* are ascertained experimentally to agree very well with the uniaxial tensile strength in wide range of brittle materials, such as graphite and marble.


2021 ◽  
Vol 833 (1) ◽  
pp. 012016
Author(s):  
D J Guerrero-Miguel ◽  
M I Alvarez-Fernández ◽  
M B Prendes-Gero ◽  
C González-Nicieza

2020 ◽  
Vol 79 (9) ◽  
pp. 4905-4916
Author(s):  
Asghar Ali ◽  
Saddam Hussain ◽  
Shehzad Khan ◽  
Awal Sher Khan ◽  
Sohail Mabood ◽  
...  

Abstract The Chakdara Granitic Gneisses (CGG) of the Indian plate and Kamila Amphibolite of the Kohistan Island Arc (KIA) along the Main Mantle Thrust (MMT) in Shigo Kas, Talash Dir Lower, indicate that tectonically induced foliations and lineations strongly affected the geomechanical properties of these rocks. The earlier S1 crenulated cleavages are well preserved in the microlithon of a well-developed ENE-WSW trending S2 crenulation cleavage. The pervasive S2 foliations, D2 fold axes, and L22 lineations are induced by NNW-SSE horizontal bulk shortening. The core samples obtained parallel and perpendicular to the main ENE-WSW trending S2 and L22 have higher and lower uniaxial compressive strength (UCS) values, respectively. The UCS and uniaxial tensile strength (UTS) average values of four core samples obtained parallel and perpendicular to the main S2 are 51.8 MPa and 12.21 MPa versus 45.65 MPa and 12.45 MPa, respectively. Core samples from the weakly foliated S-2 specimen shows little variation in the UCS and UTS values. The variation in the UCS values in the core samples cut perpendicular and parallel to the main tectonic fabric has been controlled by micro-shear zones at the contact zones of crenulated and crenulation cleavages and sigmoidal mica fish. The UCS values are higher in the core samples parallel to the pervasive S2 and L22 because the parallel shear on the sigmoidal crenulated cleavages in microlithon of the S2 and S2 mica fish counterbalance the parallel external applied load. However, the UCS values decrease in the core samples that were cut perpendicular to the pervasive S2 and L22 because the perpendicular shear on the sigmoidal crenulated cleavages in microlithon of the S2 and S2 mica fish enhances the external applied load, which lead to the failure of core samples.


Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Xiaoshuang Li ◽  
Yingchun Li ◽  
Saisai Wu

The time-dependent behaviors of the sedimentary rocks which refer to the altering of the mechanical and deformable properties of rock elements in the long-term period are of increasing importance in the investigation of the failure mechanism of the rock strata in underground coal mines. In order to obtain the accurate and reliable mechanical parameters of the sedimentary rocks at different weathering grades, the extensive experimental programs including the Brazilian splitting test, uniaxial compression tests, and direct shear tests have been carried out on the specimens that exposed to the nature environments at different durations. The correlation between the weathering grades and mechanical parameters including uniaxial tensile strength, uniaxial compression strength, elastic modulus, Poisson’s ratio, cohesion, and friction coefficient was proposed. The obtained results suggested that uniaxial tensile strength, uniaxial compressive strength, elastic modulus, and cohesion dramatically decreased with increasing weathering time, characterized as the negative exponential relationship in general. The influences of various weathering grades on fracture behavior of the rock specimens were discussed. The cumulative damage of the rock by the weathering time decreased the friction coefficient of the specimens which led to the initiation and propagation of microcrack within the rock at lower stress conditions. The obtained results improved the understanding of the roles of weathering on the mechanical properties of sedimentary rocks, which is helpful in the design of the underground geotechnical structures.


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