Analytical method of evaluating deformational properties of rock: Fid-Bau Portal

Analytical method of evaluating deformational properties of rock

Zelenskii, B. D.

Conclusions The deformation modulus of joint-zone portions is several hundred times less than the deformation modulus of the monolithic rock, and rises as a consequence of the increase in the actual contact area with increase in the compressive stresses; tending, in the limit, to reach the deformation modulus of the monolithic rock.The deformation modulus of a jointed rock massif is a variable characteristic which depends on the natural and external compressive stresses acting. The magnitude of the deformation modulus of the massif depends on the jointing characteristics, expressed by joint frequency and gap opening, and the microtopography of the walls, and also on the deformational properties of the monolithic rock in its fresh and weathered conditions.Analytical computations of deformation moduli for specific conditions in the foundations of hydraulic structures have demonstrated their satisfactory agreement with the results of field determinations of deformation moduli by methods which employ static-load plate tests.The analytical method of assessing deformational properties of rock massifs can be used to obtain deformation-modulus values for computations in the preliminary stages of design, for distribution of the field-investigation results obtained from experiment areas, to regions of the rock massif, for adjusting deformation-modulus values, according to recorded data on joints, in constructional foundation pits, with the aid of nomograms, and also in the preparation of geomechanical mock-ups, in connection with model investigations of rock foundations and abutment slopes of dams.