Coupled processes in rock mass performance with emphasis on nuclear waste isolation

Driven by the needs of engineered underground systems, the field of rock mechanics is evolving to address the interactions of in situ mechanical, thermal, hydrologic, and chemical processes and their effects on system performance. Important technical issues include understanding how the relevant loads and gradients drive in situ processes; rock mass variability, discontinuity, and heterogeneity; process and parameter scale dependence; and the degree of coupling between processes. Major challenges include scaling information from short-duration laboratory tests up to long-term, full-scale system performance and the lack of experimental investigations or simulations of fully coupled thermal-mechanical-hydrologic-chemical behavior. Technical trends and opportunities that may benefit rock engineering include applied research in reactive geochemistry, information technology for measurement systems, and modeling and monitoring combined in an observational method to improve system performance.r 2002 Elsevier Science Ltd. All rights reserved.