Quantitative World Stress Map With Three Case Studies: Geologic Repository, Gold Mining and Deep Geothermal Energy

摘要

Mechanical stress remains an enigmatic physical rock property due to the facts that stress cannot bernmeasured directly, it is difficult to visualize and it is affected by stress state-scale relations. Despite this,rnin situ rock stress has become a key parameter in rock engineering and solid Earth sciences, in general.rnIn this contribution, we focus on the state-of-the-art techniques determining the in situ stress at a givenrnsite by using our recently proposed rock stress terminology and applying the best-estimated stressrnmodel approach. In this context, we inform the reader on the existing World Stress Map databasern(WSM) of stress orientations, and our new database on lithologic in situ stress magnitudes, rockrnstrength and fracture mechanical properties, the so-called Quantitative WSM (Q-WSM). Three casernstudies highlight the road to the final rock stress model, which sometimes differs significantly from thernrecipes discussed. We address problems in obtaining reliable stress magnitudes in near-surface (0.5 km)rnhard rock of a Swedish radioactive waste disposal site, we report on stress perturbation due to minernexcavation close to a vertical dyke structure in a deep (3.5 km) South African gold mine, and werninvestigate Kaiser stress observations in a crystalline geothermal reservoir at 5 km depth applyingrnhydro-mechanical coupled discrete element modeling.