Floating foundation in a geological environment prone to sinkholes

The Gautrain Rapid Rail Link is a state-of-the-art rapid rail network currently under construction in Gauteng, South Africa. The project comprises of a link between Pretoria, Johannesburg and the OR Tambo International airport with a total length of approximately 66km. The structure described in this paper will cross a dolomite area with a 3.1km long viaduct (V5c) south of Pretoria. The site is generally underlain by dolomitic ground with occasional syenite intrusions. The area is well known for the risk of sinkhole and doline (area settlement) formation due to the erodibility of the in situ soil, cavernous ground and bedrock conditions and potentially variable water table conditions (if left uncontrolled). Sinkholes and dolines may affect the rail services and may have catastrophic consequences if left untreated. The bedrock profile is highly undulating, sometimes with deep valleys or grykes between bedrock pinnacles. The geology of the area therefore presents a significant challenge to the geotechnical and structural design teams alike. Floating foundations were considered (rafts and piled rafts) the most economical and practical solution provided that the sinkhole risk could be minimized with compaction grouting. This paper will focus on the design methodology for the geotechnical and structural design of piled raft foundation at pier P26 of Viaduct V5c, with the emphasis on modelling and determining the vertical soil structure interaction. (a) For the covering entry of this conference, please see IRRD abstract no. E218160.

• Record URL:
  http://arrbknowledge.com
• Authors:
  • KOTZE, J
  • VORSTER, E
• Publication Date: 2009-5

Language

• English

Media Info

• Pagination: 14P
• Serial:
  • AUSTROADS BRIDGE CONFERENCE, 7TH, 2009, AUCKLAND, NEW ZEALAND
  • Publisher: CONVENTION MANAGEMENT

Subject/Index Terms

• TRT Terms: Bridges; Conferences; Foundations; Geology; Ground settlement; Railroad tracks; Soil mechanics; Soils
• ITRD Terms: 3455: Bridge; 8525: Conference; 3377: Foundation; 4053: Geology; 1062: Railway track; 5792: Settlement; 4156: Soil; 5755: Soil mechanics
• Subject Areas: Bridges and other structures; Railroads; I24: Design of Bridges and Retaining Walls; I42: Soil Mechanics;

Filing Info

• Accession Number: 01143967
• Record Type: Publication
• Source Agency: TRL
• Files: ITRD, ATRI
• Created Date: Nov 16 2009 12:17PM