Deformations, arising in weak rocks subjected to the action of external forces, are functions of the time too. The theory of Voltera-Rabotnov ,  will be used for determination of these rheological deformations. For the case of nonhomogeneous, multicomponent and anisotropic rocks, possessing viscous-elastic properties, the relationship between stress tensor and deformations can be expressed in the following integral form , (4]:
(Equation in full paper)
For a function, describing creeping of the rocks under consideration a modified expression for the Abel's nucleous in the case of multicomponent and anisotropic media has been accepted in the following form:
The integration constants c1 are determined by respective boundary conditions. For the case under consideration, the boundary conditions are:
It will be noticed that expressions for rheological displacements, when the rocks possess orthogonal anisotropy, transversal isotropy and complete isotropy are obtained as particular cases.
For orthogonal-anisotropic rocks, in the expressions for rheological displacements (12) it should be put:
For transversal-isotropic rocks, except for conditions (15) and (14), the following equations are valid too:
Thus obtained expressions for rheological deformations (12) makes Possible experimental determination of the rheological parameters δij and αij for various cases of rheological anisotropy at rock creeping.
For this purpose, experimental mea- surements of longitudinal deformations Uj of a rock sample of parallelipiped Shape, with given lengths and subjected to pure compression along coordinate axes Xi should be carried out. These measurements should be taken for two various moments of time t1 and t2. Thus, for determination of the rheological parameters αij and δij a definite system of equations is obtained.
On the base of the so determined numerical values of the rheological parameters αij and δij, by formulae (12), the rheological displacements at creeping at a given moment of the time and for an arbitrary point of the rock massif can be determined.