Engineers Australia

Reflections on Modern Geotechnical Investigation:
use of the Seismic Dilatometer for design

Sergei Terzaghi


Seismic Dilatometer (sDMT) has been used for a number of recent projects in both New South Wales (NSW) and New Zealand to speed up the rate of gaining valuable information for design. Specific examples of the values obtained compared to more conventional techniques in NSW are highlighted and discussed.

The Detailed Design of the Macleay River Plain Bridge required reliable design values quickly to ensure project delivery met with programme deadlines. Conventional techniques were too time consuming and unreliable due to disturbance issues. This was already shown by the inconsistent behaviour reported during previous investigations. sDMT and CPT testing provided a solution to rapidly gather the required design information which was confirmed by high quality testing obtained during the subsequent phases of investigation.

A comparison of the results obtained via the different methods will be discussed together with possible reasons for differences and implications for design. A quick comparison with results from NSW and New Zealand will also be included.

About Sergei Terzaghi

Sergei Terzaghi is based in Sydney and leads Arup’s Australasian Geotechnics Discipline in all aspects of geotechnical engineering in both Australia and New Zealand.

Sergei has over 25 years of experience encompassing desktop and on-site geotechnical engineering in infrastructure including roads, bridges, tunnels, stations, and pipelines (water, oil, gas), embankments and dams including design, modelling, upgrades, and review services, marine and offshore geotechnics for wharves, pipelines, and moorings, foundations for structures ranging from tanks through to large multi-storey buildings in a range of site conditions and constraints.

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