ANALYSIS OF FRACTURED ROCK MASS PERMEABILITY STRUCTURE TYPES

The permeability structure of rock mass controls the macro-permeability characteristics of fractured rock mass. However, the geological factors are complex and diverse. They control the permeability structure of rock mass. As to the actual engineering rock mass, the rock permeability structures are the hybrid types that are formed by basic permeable structure types. Through practical research at the field and statistical analysis, this paper summarizes five types of basic permeable structures that are widespread and four types of hybrid permeability structures and percolation characteristics in fractured rock mass. The types are Ⅰ-Ⅱ, Ⅲ-Ⅳ, Ⅰ-Ⅱ-Ⅲ and Ⅰ-Ⅲ-Ⅳ respectively. Using a project instance, this paper analyzes the hybrid permeability structure types of the fractured rock, which are spread in the underground cavern and the switch stations of hydropower stations in southwestern China. At last, it is concluded that based on hybrid permeability structures, the hybrid types of permeable structures are mainly Ⅲ-Ⅳ and Ⅰ-Ⅱ-Ⅲ. Also, the results are more in line with the actual situations.