Application of pile test data for geotechnical site characterisation of Seaford and Carrum

Victoria’s Level Crossing Removal Project is removing 75 level crossings across Melbourne to improve safety, reduce congestion and allow more trains to run more often. The Southern Program Alliance (SPA) is delivering the Frankston line section – a $3 billion upgrade removing 18 level crossings and building 12 new stations. The Seaford level crossing removal works are complete, and those in Carrum, Mentone and Cheltenham are under construction.

At Seaford, dynamic pile testing analysis of continuous flight auger (CFA) pile foundations and rigid inclusions, using pile driving analyser (PDA) testing and Case Pile Wave Analysis Program (CAPWAP) analysis, was carried out to validate pile design assumptions. The results were correlated to in-situ and laboratory soil classification testing to characterise the site’s geology in terms of pile performance. This enabled the testing results to be used to refine the geotechnical design of CFA pile foundations for the Carrum rail viaduct, about two kilometres north of Seaford, in the same geology.

This paper discusses characterisation of geological units encountered at Seaford using pile test data, and the subsequent geotechnical design of the Carrum rail viaduct foundations. Comparing soil classification tests from Seaford to Carrum showed good agreement, and satisfied the designers that the Seaford pile test data was applicable for use in the foundation design at Carrum. Furthermore, this paper compares the correlation of geotechnical strength parameters with available empirical correlations, and comments on the benefits and limitations of this site classification and design approach.