Rock-mass block index and its engineering practice significance

Abstract

Rock\|mass block index ( RBI ) for indicating the properties of rock is proposed. The index is defined as the sum of weighted drill\|core recovery ratio for differnet lengths. Based on the current code for classification of rock\|mass structure in China, 5 grades of length are suggested, namely 3-10cm,10-30cm,30-50cm,50-100cm and 100cm. The correlation analyses of relationship between RBI and rock quality designation, RBI and coefficient of rock\|mass sound\|degree, RBI and deformation modulus of rock\|mass show that the RBI can synthetically reflect the rock\|mass block properties and its structure.