Mechanical properties and instability analysis of concrete specimens with horizontal holes of different diameters

Uniaxial compression tests were carried on 12 concrete specimens with six different diameter holes using a rigid test machine, and the stress–strain relationship was analyzed in hole specimens. The effects of diameters specimen strength, elastic modulus, Poisson’s ratio studied, failure form instability mode evaluated. results show that larger strength specimen, axial horizontal strains. As increased from 0 to 50 mm, modulus reduced. decreasing trend slowed down, relationships between could be represented by negative liner functions. Poisson waves increase mm. A crack 0–20 mm started at upper lower diagonal angles wall; 30–50 left right parts wall. divided into shear dislocation planar splitting instability.