Deformation anisotropy of soft rock = Anizotropija deformacijskih svojstava meke stijene

Bedding, being a typical feature of sedimentary rocks, is a cause of inherent anisotropy of deformation properties of rock mass. Results of uniaxial and triaxial, short_term and creep tests conducted by the authors on the specimens of a soft sedimentary rock - marl are presented in this paper. Interpolation of results of the short_term tests enabled for determining the parabolic dependence of secant modulus of deformability on angle (a) between load and natural bedding planes in the interval from 0 to 90 degrees. The time-dependent deformation response is described by determining the dependence of parameters of the modified Wallner’s model on the angle a in the interval from 45 to 90 degrees, based on the results of the performed creep tests.