Rock Mass Rating (RMR) Field Survey Sheet

The RMR system, developed by Bieniawski in the 1970s, is one of the most widely adopted empirical rock mass classification methods. The Field Survey Sheet serves as the primary instrument for consistent, on-site data acquisition—ensuring traceability, repeatability, and minimal subjectivity through predefined rating tables and descriptive anchors (e.g., 'joints slightly rough, undulating, no coating' corresponds to a specific score). Each parameter is assessed independently: uniaxial compressive strength is estimated via point load tests or laboratory data; RQD is measured from drill core recovery; joint spacing and condition are logged visually or with scanline surveys; groundwater inflow is quantified in liters per minute per 10 m tunnel length; and orientation adjustment accounts for adverse joint geometry relative to excavation geometry using stereographic projection or simplified charts. The sheet often includes space for sketches, photographs, location metadata (borehole ID, chainage, elevation), and engineer verification signatures—supporting QA/QC protocols and integration into digital geotechnical databases. In practice, RMR values guide support design (e.g., bolt spacing, shotcrete thickness), excavation method selection (e.g., drill-and-blast vs. TBM), and risk assessment during construction, especially in mining and civil tunneling projects.