The length of pre-existing fissures effects on the mechanical properties of cracked red sandstone and strength design in engineering.

It is important to study the mechanical properties of cracked rock to understand the engineering behavior of cracked rock mass. Consequently, the influence of the length of pre-existing fissures on the strength, deformation, acoustic emission (AE) and failure characteristics of cracked rock specimen was analyzed, and the optimal selection of strength parameter in engineering design was discussed. The results show that the strength parameters (stress of dilatancy onset and uniaxial compressive strength) and deformation parameters (axial strain and circumferential strain at dilatancy onset and peak point) of cracked rock specimen decrease with the increase of the number of pre-existing fissures, and the relations which can use the negative exponential function to fit.