Geotechnical Properties of Rock Masses : their Control on Slope Form and Mechanisms of Change along the Napier Range, Western Australia,
R.J. Allison, A.S. Goudie, N.J. Cox
Slope form and the mechanism of change which slope profiles exhibit are frequently subject to scrutiny by geomorphologists. However, the majority of studies do not consider fundamental material properties and rock mass geotechnical characteristics. The results presented highlight the importance of synthesising standard geomorphological site investigation techniques with quantifiable rock geotechnical parameters, in order to understand slope form and development. Field research has been undertaken along the Napier Range of the Kimberley Region, Western Australia. The Napiers are an extensive, upraised, Devonian limestone reef, alon which a number of characteristic slope profiles can be identified. Laboratory studies of yield strength, stress-strain characteristics, elastic properties and discontinuity parameters have been conducted on material sampled at sites representative of each slope profile type. The results suggest that highly concave slopes have formed in limestone which exhibits little deformation before yield, has a high modulus of elasticity and few irregular fractures. Convexo-concave slopes, on the other hand, are characteristic of material which displays a greater ability to strain below yield, a relatively low modulus of elasticity and a pronounced discontinuity pattern. It is the combination of the field investigations and laboratory study which most successfully explains variations in slope form.