DRIVEN PILES IN CLAY - THE EFFECTS OF INSTALLATION AND SUBSEQUENT CONSOLIDATION

This paper describes the results of numerical analysis of the effects of installing a driven pile. The geometry of the problem has been simplified by the assumption of plane strain conditions in addition to axial symmetry. Pile installation has been modelled as the undrained expansion of a cylindrical cavity. The excess pore pressures generated in this process have subsequently been assumed to dissipate by means of outward radial flow of pore water. The consolidation of the soil has been studied using A work-hardening elasto-plastic soil model which has the unique feature of allowing the strength of the soil to change as the water content changes. Thus it is possible to calculate the new intrinsic soil strength at any stage during consolidation. In particular the long-term shaft capacity of a driven pile may be estimated from the final effective stress state and intrinsic strength of the soil adjacent to the pile. A parametric study has been made of the effect of the past consolidation history of the soil on the stress changes due to installation of the pile. The results indicate that for any initial value of overconsolidation ratio, the final stress state adjacent to the pile is similar to that in a normally one-dimensionally consolidated soil except that the radial stress is the major principal stress. A method is described whereby the model of pile installation and subsequent consolidation may be extended to clays which are sensitive. The method is used to predict changes in the strength and water content of soil adjacent to a driven pile which compare well with measurements from two field tests on driven piles. It is also shown that the rate of increase of bearing capacity of a driven pile may be estimated with reasonable accuracy from the rate of increase in shear strength of the soil predicted from the analysis. (Author/TRRL)

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/00168505
• Corporate Authors:

  Institution of Civil Engineers

  One Great George Street, Westminster
  London,   United Kingdom  SW1P 3AA
• Authors:
  • RANDOLPH, M F
  • Carter, J P
  • Wroth, C P
• Publication Date: 1979-12

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 361-393
• Serial:
  • GEOTECHNIQUE
  • Volume: 29
  • Issue Number: 4
  • Publisher: Thomas Telford Limited
  • ISSN: 0016-8505

Subject/Index Terms

• TRT Terms: Bearing capacity; Clay; Clay soils; Consolidation; Elasticity (Mechanics); Forecasting; Geometry; Installation; Moisture content; Pile driving; Piles (Supports); Plasticity; Pore water pressures; Shear strength; Soil stabilization; Soil structure interaction; Soil water; Soils; Strength of materials; Stresses
• Uncontrolled Terms: Soil consolidation
• Old TRIS Terms: Soil water content
• ITRD Terms: 3085: Bearing capacity; 4177: Clay; 5791: Consolidation (soil); 3641: Driving (pile); 5912: Elasticity; 132: Forecast; 3840: Installation; 5920: Moisture content; 3399: Pile; 5922: Plasticity; 5762: Pore water pressure; 5531: Shear; 5544: Strength (mater)
• Subject Areas: Geotechnology; Highways; Maintenance and Preservation;

Filing Info

• Accession Number: 00309852
• Record Type: Publication
• Source Agency: Transport Research Laboratory
• Files: ITRD, TRIS
• Created Date: Jun 26 1980 12:00AM