Interpretation of geometrical characteristics of joints using drill core

Understanding joints is becoming increasingly important in South Korea owing to the development of plans for high-level waste disposal. This study examined drill cores to assess the morphology of joints in five areas with different rock types. The depths and dip angles of 14,169 joints were measured, and the joints were then classified based on their dip angles. Joint spacings within each set were statistically analyzed and fitted to five statistical distribution models: double Weibull, exponential, generalized log-logistic, gamma, and lognormal. Results for each given type of rock showed similar dip angles but varying depths. The observed joint spacings were most accurately fitted using the lognormal distribution. The results of this study will provide insights into the distributions of joints in South Korea and can be used in numerical modeling and stability assessments.