ROCkurven

ROCKurven is a term used in geotechnical engineering and rock mechanics to denote a parametric curve that represents the relationship between rock strength indicators and a controlling variable, typically confining pressure or moisture content. The name combines rock with the word for curve in several European languages, reflecting its function as a curve-based summary of lab and field data.

In practice, ROCKurven is generated by compiling laboratory and field test results for a rock material or rock mass. Data such as uniaxial compressive strength, indirect tensile strength, and triaxial test results are plotted against a chosen variable, such as effective stress or moisture. A nonlinear regression or constitutive model is then fitted to obtain a curve that can be used to predict rock behavior under different conditions. The resulting curve can help calibrate design methods or numerical models and serves as a compact representation of material variability.

Applications of ROCKurven include slope stability analyses, underground excavation design, and ground control planning. It is particularly useful when material properties are highly variable or when in-situ conditions differ from standard laboratory conditions. By providing a visual and quantitative summary, ROCKurven supports engineering judgment and helps inform safety and cost considerations in rock engineering projects.

Limitations of the approach include dependence on data quality and representativeness, scale effects, and rock anisotropy. ROCKurven should be used as a supplemental tool alongside site investigations, multiple data sources, and established failure criteria (such as Mohr–Coulomb or Hoek–Brown) to ensure robust design decisions.