Sydney, NSW Chapter

Young Geotechicnal Professionals’ Night


Peter Retsos: Investigation of the Piles Creek Embankment Collapse
An embankment at Piles Creek failed during heavy rain in June 2007. Five deaths occurred when a vehicle then drove into the void created by the collapse. The subsequent investigation of the collapse was undertaken by Connell Wagner in a collegial manner with expert representatives from the RTA and Gosford City Council. In this presentation, Peter will discuss the methods used during the field investigations and the advantages and disadvantages of undertaking a collegial investigation. He will also reflect on the benefits and skills gained from examining a failure of this nature.

Kathryn Pike: Jointing and Dyke Structures in Top Ryde, Sydney
The ongoing construction of the Top Ryde Shopping Centre involves excavation to depths varying between 10m and 25m below ground surface. Preliminary investigations identified an igneous dyke in the northern corner of the site and high angle joints. These features have been progressively revealed during the excavation process. Kathryn will present the results of mapping, analysis and interpretation of the geological and structural features encountered. The study of such features will allow engineers to make improved predictions of areas of rock affected by dyke structures and their associated jointing.

Ted Tse: Ground Improvement for Rail Embankment Construction on Soft Ground
A 4.3km railway line is proposed as part of the development of the Coal Export Terminal 3 on Kooragang Island, Newcastle. The proposal involves the construction of embankments up to 10m high, to be formed over soft ground, water ponds, coal washery rejects and slag bunded emplacement cells. Investigation and testing for the site included two stages of field investigation, laboratory tests and a full scale trial embankment. Ted will present the challenges encountered in the design of the rail embankment, including the investigation and selection of various ground improvement options.

David Oliveira: Modelling of Infilled Rock Discontinuities
One of the most challenging tasks when designing structures on or within a rock mass is the modelling of the mechanical behaviour of the rock. This is typically due to the rock mass comprising interlocking discrete blocks and the varying conditions of the rock joint surfaces. Among these contact surfaces, infilled rock joints are likely to be the weakest planes. David will present a review of studies involving the shear behaviour of infilled rock joints and some of the most recent advances in modelling. A new semiempirical yielding criterion for infilled rock discontinuities will be discussed.

Engineers Australia members participating in AGS technical sessions can record attendance on their personal CPD logs. Members should refer to Engineers Australia CPD policy for details on CPD types, requirements and auditing guidelines.