Videos of presentations made at Australian Geomechanics Society events will be periodically made available.
Videos
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Chris Clayton – Rankine Lecture
This lecture reviews what is now known about the complex stiffness behaviour of soil and weak rocks in the context of elasticity, arguably the simplest of constitutive behaviour. Drawing on experience gained through field observation and numerical modelling, the case is made for the routine use of non-linear anisotropic stiffness. The determination of the parameters required is then explored, and the usefulness of advanced triaxial testing, and dynamic laboratory and field testing examined.
Click here to view the video: Chris Clayton – Rankine Lecture
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Dr Paul Marinos
The integration of site geology with engineering requirements is the basis of Engineering Geology, and there continues to be a need to describe site geology in terms appropriate for the analyses of deformation and stability of ground in situ. Two developments hold the potential to improve such description: the characterization of soil and rock, and the wider use of numerical modeling. Methods of characterization can now be tested with the aid of numerical analyses, and the suitability of the predictions they lead to can be tested with site instrumentation.
Since the attempt by Terzaghi in 1946 to describe the characteristics of rock masses, numerous rock mass classifications have been developed. Hoek and Brown (1980) set out to develop a failure criterion and a classification system, the Geological Strength Index (GSI), specifically for the purpose of designing tunnels, slopes or foundations in rocks. Here the geological character of rock material, together with a visual assessment of the mass that forms, are used as a direct input for the selection of parameters relevant for the prediction of rock mass strength and deformability. GSI has considerable potential for use in rock engineering because it permits the manifold aspects of rock to be quantified, enhancing geological logic and reducing engineering uncertainty. A detailed description of GSI is presented with suggestions for its use and discussion on its limitations. A number of examples from designs of engineering structures conclude the presentation.
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46th Terzaghi Lecture – Geosynthetic Reinforced Soil: From the Experimental to the Familiar
The lecture begins with a historical review of reinforced soil technology, from the ancients, the developments by H. Vidal and K. Lee on Terre Armée and Reinforced Earth, the early uses of geosynthetics for soil reinforcement in France (Bidim), Sweden (Wager and Broms), and the USA (USFS, FHWA, J. R. Bell, T. A. Haliburton, B. R. Christopher and others).
The advantages and basic behavior of geosynthetic reinforced soil (GRS) are presented along with an overview of current design procedures, and with reference to UW analytical research results. Practical suggestions are given for dealing with creep, pullout, and backfill drainage. Geosynthetic properties and then discussed, again with reference to UW research results.
Although GRS is quite a mature development, a few technical and professional issues remain; primarily, too many failures of these structures occur. Reasons for these failures and some suggestions as to what the profession can do about them are presented.
The lecture ends with several examples of successful applications of GRS and reinforced soil technology.
