ABSTRACT
The rock mechanical input parameters, which are widely used in design studies, are uniaxial compressive strength (UCS),Young modulus (E), Poisson ratio (υ), and the maximum-minimum principal stress relationship (σ1, σ3), respectively. The loading velocities and specimen dimensions for the tests are effective parameters because test results change. Therefore, test procedures were published by the International Society for Rock Mechanics (ISRM 1978, 2007) and the American Society of Testing and Materials (ASTM 1986). The suggested loading velocity for uniaxial and triaxial compression tests is betweeen 0.5-1 MPa/sec for both standards. Although standards for specimen dimensions were developed in both cases, it is questionable whether these standards are valid for special rock materials like ductile and brittle rock, such as coal and rock salt.
