Viscoelastic analysis of the creep characteristics of interlayered rock specimens under uniaxial compression

Creep properties of interlayered rock mass often encountered in rock engineering, significantly affect the safety and long-term stability of practical engineering. In this study, the theoretical equations of creep strain for interlayered rock specimens when the uniaxial compression loading was applied perpendicular to or parallel with bedding plane were derived. The laws of viscoelastic deformation for soft-hard interlayered rock specimens, soft-soft interlayered rock specimens and hard-hard interlayered rock specimens were also discussed, respectively. The creep deformation characteristics obtained from the numerical simulation and the theoretical analyses were consistent, confirming the correctness of the calculation method proposed in this paper. The results showed that the viscoelastic deformation of interlayered rock specimens was not only related to the volume ratio of rock layers, but it also was affected by the spatial position of the layered structure. In addition, creep properties of hard and soft rock layers were characterized by stable creep model and unstable creep model, respectively. The influences of volume content, number of strips, buried depth, spacing and angle of soft rock interlayer on the creep properties of soft-hard interlayered rock specimens were also analyzed.