关键词: 裂隙测量, 张开度, 岩体渗透性, 数字图像处理, 中轴算法

Abstract: The fracture aperture affects the permeability of fractured rock mass greatly. It is significant for characterizing the inner structure and evaluating the permeability of fractured rock. However, as the morphology of fracture in nature is diverse and complex, the traditional aperture measurements have some limits when measuring the aperture. In order to measure the fracture aperture more accurately and efficiently, on the basis of summarizing and analyzing the methods of fracture aperture measurement proposed by the former researchers, an improved Central Axis Algorithm of Aperture according to the definition of the fracture aperture was proposed. In order to validate the reliability and practicability of this method, three typical fractures with different morphological complexity were collected from the cataclasite in the fault zone of a high-level radioactive waste repository candidate site, and their fractures were measured by the CAAA. Compared with the results obtained by two other traditional measurement methods, the Minimum Enclosing Rectangle Algorithm and the Central Line Algorithm, the CAAA result is closer to the real condition, which proves that the CAAA is simple in principle and easy to programming, and has high reliability and applicability. Therefore, the proposed method provides a new practical way to accurately measure the fracture aperture.

Key words: measurement of fracture, aperture, rock permeability, digital image processing, central axis algorithm