Abstract: The past partitioning methods of dominant groups are all based on the orientation information of structural planes， and they do not consider the effect of mechanical characteristics of structural planes and partitioning indexes on dominant groups partitioning， which may lead to the wrong partitioning results. In this respect， the mechanical characteristics quantified by CSPC(a classification method of structural plane character) were introduced for partitioning the dominant groups based on the characteristics of structural planes， and the partition of dominant groups was achieved by an iterative variable fuzzy model. It was concluded that the influence of mechanical characteristics on dominant groups partitioning can not be ignored. Shear strength parameters can be forecast by the partitioning method of dominant groups based on the characteristics of structural planes， which may lay the basis for the subsequent block stability analysis.

Key words: characteristics of structural plane, variable fuzzy model, dominant group partitioning, shear strength parameter, analytic hierarchy process