CONSTRUCTION OF BORED PILES IN WEATHERED ROCKS

The conventional methods of constructing bored piles socketed into weathered rocks were critically investigated during the construction of the West Gate Freeway, South Melbourne. The rock socket designs involved some construction-related assumptions, which were found to be invalidated by construction practice. The socket base resistance was affected by (I) the extent of the problem of not founding on the expected end bearing layer, (II) the degree of base cleanliness, (III) the amount of disturbance of the base materials, (IV) the presence of a clay layer on the base suuface, and (V) the flatness of the base. A socket inspection device (SID) was developed to inspect and record the cleanliness of pile bases. Because of the unsatisfactory results observed after using conventional base cleaning methods, more effective base cleaning tools were also developed. The socket side resistance was affected by (I) the extent of the problem of not forming a socket with the expected side-wall materials, (II) insufficient wall roughness, (III) the amount of disturbance of wall materials, (IV) the stability of the socket walls, and (V) the thickness of a layer of filter-cake, remoulded clay, and/or redistributed base debris. The report also contains a description of siss, a device for sampling these layers. The problems of bentonite construction of bored piles in weathered rocks is recorded, together with some recommended procedures, especially for minimising the build- up of filter-cake. Also, certain problems were observed regarding (I) the casing installation, (II) the drilling of the socket to the design dimensions, (III) the structural integrity of the concrete, and (IV) the safety of personnel constructing and inspecting sockets. (Author/TRRL)

• Corporate Authors:

  Road Construction Authority

  60 Denmark Authority
  Kew, Victoria,   Australia 
• Authors:
  • HOLDEN, J C
• Publication Date: 1984

Media Info

• Features: Figures; Photos; References; Tables;
• Pagination: 136 p.

Subject/Index Terms

• TRT Terms: Base course (Pavements); Bentonite; Bridges; Cast in place concrete; Clay; Cleaning; Concrete; Construction; Construction management; Construction safety; Design; Drilling; Evaluation and assessment; Explosives; Foundations; Inspection; Installation; Methodology; Pavement layers; Personnel; Rocks; Safety; Sampling; Sockets (Electricity); Structures; Support piles; Weathered rock; Weathering
• Geographic Terms: Australia
• Old TRIS Terms: Bases; Bored pile; Casing /process/; Explosive charge limitation; Sockets
• ITRD Terms: 8006: Australia; 4186: Bentonite; 3455: Bridge; 4781: Cast in situ concrete; 4177: Clay; 3849: Cleaning; 4755: Concrete; 3655: Construction; 9011: Design (overall design); 3871: Drilling; 3355: Engineering structure; 9020: Evaluation (assessment); 3377: Foundation; 3840: Installation; 2952: Layer; 9102: Method; 3399: Pile; 4154: Rock; 1665: Safety; 5281: Weathering
• Subject Areas: Bridges and other structures; Construction; Design; Geotechnology; Highways; Maintenance and Preservation; Safety and Human Factors; Society; I53: Construction of Bridges and Retaining Walls;

Filing Info

• Accession Number: 00399454
• Record Type: Publication
• Source Agency: ARRB
• Files: ITRD, TRIS, ATRI
• Created Date: Aug 25 2004 1:42AM