Modification of Three Dimension Hoek-Brown Criterion Based on Elastic Strain Energy

Abstract:

The H-B strength criterion was revised from the energy point of view to improve its accuracy and applicability， which was different from the previous methods of improving rock mass characteristic parameters. Based on the fact that elastic strain energy release was the intrinsic mechanism of rock failure，researches were carried out： The general expression of existing H-B criterion was summarized and its energy mechanism in determining material failure was clarified， revealing that the H-B criterion was both an empirical strength criterion and an energy-type strength criterion expressed by elastic strain energy， which led to the key to improving the calculation accuracy of the H-B strength criterion.The H-B criterion was obtained based on the best fit of the strength data the relationship between the criterion and the theoretical expression of elastic strain energy， introducing material deformation parameters to replace Poisson's ratio in elastic strain energy to establish a modified three-dimension H-B criterion including only three parameters.The further theoretical analysis shows that the modified three-dimension H-B criterion is a set of strength criteria with deformation parameters as parameters， when the deformation parameter is equal to 0.5， it degenerates into the existing three-dimensional H-B criterion； Finally， the true triaxial test calculations show that the modified three-dimension H-B criterion can better describe the failure characteristics of the rock， the calculation results are more accurate， and the internal mechanism that produces the above results is analyzed.

Key words:rock mechanic;three-dimension Hoek-Brown criterion;elastic strain energy;Poisson’s ratio