| Abstrakt: |
The article proposes an alternative method for determining the modulus of deformation of fractured - block rock masses weakened by mutually orthogonal systems of joints when the angles of their inclination to the surface of the rock mass (dip angle) change. The deformation of the model of rock mass is considered within the linear section of the deformation curve a=f(ε) (after closing the cracks), provided that the quasi- continuum criterion is met. The values of normal - kn and tangential - ks stiffness are used as elastic characteristics of joints.It is shown that to determine the deformation characteristics of a block medium weakened by systems of joints with different dip angles, it is unlawful to use the laws of mechanics of a continuous elastic body, since the opening of interblock joints is observed when performing numerical experiments. The discrepancy between the results of numerical and analytical calculations is up to 40%. It is proposed to use for these purposes the equation obtained on the basis of the method of experimental planning and regression analysis of the results of numerical modeling. The presented equation allows, depending on three independent factors: the modulus of elasticity of the rock block - Eo, the rock quality designation index - RQD and the dip angles of systems of mutually orthogonal ioints – α, to determine the modulus of deformation of the rock mass. The accuracy of calculations does not exceed 20%, which corresponds to engineering accuracy and can be used at the preliminary stage of engineering structures design. The article presents schemes and graphs of deformation of a block models, characterized by arbitrary selected combinations of values of independent factors. The results of the study also showed that in the presence of anisotropy, the rock mass can be considered as a conditionally continuous, isotropic medium, provided that the anisotropy coefficient does not exceed 1.5. [ABSTRACT FROM AUTHOR] |
