Development of new relationships for estimating the in-situ stress in the Canadian Shield based on geological conditions

The accurate assessment of in situ stress is fundamental for ensuring the stability of rock masses in deep underground projects, particularly within the geologically complex Canadian Shield. Despite decades of research, stress-depth relationships remain uncertain, often due to oversimplified approaches that categorize stress data into arbitrary depth domains without adequate geological context. This study presents a novel methodology that subdivides the stress database into six distinct groups, defined by lithological and structural similarities, to better reflect the region's geological diversity. By integrating geological understanding with advanced statistical analyses, we developed stress-depth relationships that are both statistically robust and geologically representative. Our findings reveal that conventional depth-domain classifications fail to account for regional variations influenced by tectonic processes. Through detailed regression analyses, we identified key geotectonic events that have significantly shaped stress distributions within the Shield. The resulting equations for critical stress parameters provide an improved basis for assessing in situ stresses, offering valuable insights for geomechanical modeling and the design of underground structures. This research underscores the necessity of combining geological expertise with quantitative methods to address the inherent complexities of stress fields in challenging geological environments like the Canadian Shield.