Uniaxial compression test was conducted on sandstone with a single pre-existing flaw at various inclined angles. Employing crack propagation measuring techniques and relevant fracture criteria

some conclusions are drawn as follows. (1) The crack initiation angles of the sandstone specimen obtained from both theory and experiments increased with increasing flaw inclined angle. (2) Using a fracture criterion

the appearance of a anti-wing cracks at the tip of the crack of the sandstone specimen was attributed to shear failure. (3) Under uniaxial compression

crack propagation in the sandstone specimen is influenced by the single flaw inclined angle; a small flaw inclined angle it is not easy to crack initiation

while the large flaw inclined angle

allowed easy crack initiation (4) Under uniaxial compression

crack propagation in the sandstone specimen

which was influenced by a single pre-existing flaw

was unstable when the flaw inclined angle was small; and stable when the angle was large. (5) For the sandstone specimen

the average crack propagation velocity for A and B sides of the crack tip decreases with increasing flaw inclined angle.