MEMORY EFFECTS IN ROCKS (REVIEW)

The given review indicates that both in our country and abroad an active scientific search is being carried out in the area of memory effects of rocks. The results obtained confirm the prospects of using these effects in geocontrol, mainly for solving problems related to evaluating the space-time dynamics of the stress-strain state of rocks and to obtaining quantitative estimates of stresses in the mass. At the same time, it follows from an analysis of the material presented that the degree of study of various memory effects is different and decreases in accordance with the order of their examination in the present review. The absolute majority of works have an experimental character. Attempts at a theoretical interpretation of the observed effects are single and at present have not permitted creating physicomathematical models adequately explaining their nature and mechanisms. The regularities of memory effects under conditions of triaxial unequal-component loading of rocks are virtually unstudied. Furthermore, there are no unequivocal answers to questions: about the characteristics of manifestations of memory properties in rocks of various genetic groups and deposits; about the effect on these manifestations of the regimes of the initial (natural) action and secondary action directed at extracting the information contained in the memory; about the limiting (maximum and minimum) levels of thermodynamic actions which are still remembered by the rock; about the time of preservation of memory as a function of the level of noise effects of various physical nature, etc. The search for answers to these question today is hampered by the absence of unified method approaches in investigations of memory effects, without which a correct comparison and generalization of their results is impossible. The authors are grateful to Yu. M. Kartashov and L. L. Panas'yan for offering certain materials used in the present work. © 1995 Plenum Publishing Corporation.