Study on the influence of statistical geometrical characteristics on the permeability tensor of fractured rock masses by the equivalent pipe network method

• Published in: Computers and geotechnics Vol. 165; p. 105868
• Main Authors: Mi, Xianzhen, Yu, Liyuan, Zhang, Jing, Liu, Richeng, Hu, Bowen, Wei, Chao
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-01-2024
• Subjects: Beishan I area; Discrete fracture network; Permeability tensor; Representative elementary volume; Statistical geometrical characteristic; Permeability tensor; Representative elementary volume; Discrete fracture network; Beishan I area; Statistical geometrical characteristic
• ISSN: 0266-352X; 1873-7633
• DOI: 10.1016/j.compgeo.2023.105868

The permeability of the host rock of the nuclear waste underground repository is one of the most keys for estimating the potential risk for nuclide waste to escape. Therefore, a three-dimensional discrete fracture network (DFN) model using the Monte Carlo method is generated based on the statistical geometrical characteristics of fracture network in Beishan I area which is selected as the site for constructing the nuclear waste repository in China. And the permeability of Beishan I fractured rock masses is calculated through the equivalent pipe network (EPN) method and representative elementary volume (REV) of it is determined. A rotating algorithm is developed to calculate different direction permeability. Furthermore, the influence of fracture statistical geometrical characteristics on REV size is explored by creating a series of DFN models with varying log-normal distribution of side lengths. The results show that the REV size of the Beishan Ⅰ area is 1.66 × 105 m3 and the corresponding principal permeability direction is 111.29°/75.36°. The REV size and permeability both increase with the increment of the mean and variance of the log-normal distribution increases. And with the increase of mean and variance, the growth rate gradually accelerated.