Volume 29, Issue 2 (March 2006)
An Empirical Relationship between Rock Structure Rating and Rock Mass Rating
Prediction of support pressures for underground openings is one of the most difficult tasks in rock engineering. The difficulties associated with the selection of reliable material properties, laws of material behavior, stress environment, etc. (which are essential for satisfactory application of analytical methods and numerical techniques) and the simplicity of the classification systems have collectively contributed to the popularity of empirical approaches for support design. The unpredictable nature of weathering enhances the complexity of the assessment of rock masses. In this study an attempt has been made to derive a simple relationship between rock structure rating and rock mass rating, which will permit accurate estimation of engineering properties of rock using easily measured parameters. The data used to formulate the empirical relationships came from tests conducted on rock samples collected from 45 boreholes at various locations between Visakhapatnam and Koraput (India).