Fundamentals of rock joint deformation

Strength, deformation and conductivity coupling of rock joints

The measurement of surface profiles is presented as a useful and simple approach to classifying statistically the essential features of rock joints. After introducing the reader to some existing analytical joint contact models for normal loading, a discrete numerical technique is developed. Using this technique the mechanical behaviour of a number of different slate joints is examined. The functional relationships between nominal stress, stiffness, true contact area and initial aperture are shown, for this class of joints, to be surprisingly simple. Experimental evidence is used to substantiate the numerical results. From the point of view of in-situ joint stiffness and hydraulic conductivity, numerical predictions seem feasible provided the degree of “mating” at some known stress level can be determined.

Determination of stiffness and other joint properties from roughness measurements

Models for normal fracture deformation under compressive loading

The nature of roughness scale effects and the limited use of simple regular profiles are discussed. Some details of the empirical Barton-Bandis and Ladanyi-Archambault models are critically reviewed. It is shown that true roughness amplitude exhibits an increasing magnitude with scale in contrast to the Barton-Bandis model.

Prediction of shear behaviour of joints using profiles

This study explores several aspects of the 'discontinuous' approach to prediction of settlements of foundations on jointed rock. The first part presents the results of experiments with numerical an...

D. F. Coates

Papers

Deformability of joints and its relation to rock foundation settlements