Evaluation of
Shear Strength Parameters in Unreinforced and Shotcrete Reinforced Coal through
Experimental and Numerical Methods
Bhat Ilyas, S. Rupali and Kumar Arvind
Disaster Advances; Vol. 15(7); 10-17;
doi: https://doi.org/10.25303/1507da10017; (2022)
Abstract
The shear strength of coal mines forms the most significant aspect in the evaluation
of mining disasters. A series of direct shear strength tests were conducted on intact
coal specimens and coal-shotcrete specimens to evaluate the shear strength characteristics
of the coal and coal-shotcrete interface. The tests were carried out under 1, 2
and 3 MPa of normal pressure respectively. The peak shear strength in intact coal
specimen reaches its maximum value of 3.96 MPa under 3MPa of normally applied pressure
while the shotcrete-coal interface has an estimated peak shear strength of 0.73,
0.80 and 0.86 MPa under the normal pressure of 1, 2 and 3 MPa respectively.
Mohr-Coulomb model parameters such as adhesion strength and angle of adhesion were
further determined that were used for the design and evaluation of shear strength
of in situ coal mines. Numerical simulations of coal-shotcrete and intact coal specimens
were performed using the Mohr-Coulomb model in Abaqus software and the numerical
results obtained were found in good agreement with experimental results exhibiting
peak variation of less than 15%. Further, ultrasonic pulse velocity test measurements
were performed on coal specimens to evaluate the dynamic shear strength parameters
and the parameters obtained were found to be enhanced compared to static strength
parameters.
