Physics-informed generative adversarial networks for synthetic uniaxial compressive strength data generation in geotechnical applications

Data-driven rock mechanics has long been constrained by a chronic deficit: coordinated laboratory measurements of uniaxial compressive strength (UCS) and its physically related properties are not only limited in number but also unevenly distributed across rock types. To address this constraint, the present study proposes a diversity-tuned physics-informed generative adversarial network—termed PI-GAN—designed to produce synthetic UCS, porosity, and bulk-density data that preserve the fundamental mechanical relationships inherent to rock materials. The framework integrates adversarial learning with an intact-rock strength-envelope constraint, category-specific UCS–porosity–density correlation losses, moment and covariance matching, feature-envelope penalties, and a pairwise-distance diversity term. The model was calibrated on 944 complete records drawn from the P 3 petrophysical database, grouped into dense crystalline, volcanic, pyroclastic, and sedimentary rock categories. The trained PI-GAN generated 944 synthetic samples, increasing the usable dataset to 1,888 records. The synthetic data preserved the dominant correlation structure, with the overall UCS–porosity correlation shifting from − 0.598 to − 0.675 and the UCS–density correlation changing from 0.566 to 0.650. Category-specific Fisher z-tests showed non-significant differences for 11 of 12 correlation pairs, with an average absolute correlation difference of 0.036. Distributional validation yielded a mean Kolmogorov–Smirnov statistic of 0.181, while diversity diagnostics produced a mean pairwise-distance ratio of 0.703 and a near-duplicate rate of 0.0%. Strength-envelope sensitivity checks returned zero violations across tolerance levels from 10% to 50% of category mean UCS. The results indicate that the proposed PI-GAN can provide physics-consistent augmentation data for machine-learning development in data-scarce geotechnical applications, while serving as a complement to, rather than a replacement for, site-specific laboratory testing.