Numerical Study of the Effect of Verification Core Hole on the Point Bearing Capacity of Drilled Shafts
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 136, Issue 9
Abstract
This paper presents a numerical investigation of the effect of a verification core hole on the point bearing capacity of drilled shafts installed in clay shales. The verification core extracted at the shaft tip may reduce the point bearing capacity of drilled shafts as a result of degradation of clay shales and imperfect core hole infill. Finite-element analyses were conducted using the Mohr-Coulomb model with total stress material parameters estimated from laboratory tests. A series of load-displacement curves was calculated for 1 cycle of air drying and wetting; different drying durations and different core hole conditions were considered; and the point bearing capacity was determined at 3 and 5% shaft diameter displacements. The numerical analyses indicate that the point bearing capacity of drilled shafts with a verification core hole does not decrease for most cases, and the maximum reduction merely reaches 5%. Recommendations are made to reduce the effect of the verification core extracted at the shaft bottom during construction.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
This research was conducted through the University of Texas at Austin with financial support from the Texas Department of Transportation (TxDOT), and the article is partly supported by project UNSPECIFIEDPE98361 of Korean Ocean Research and Development Institute (KORDI). PLAXIS 8 was donated by PLAXIS BV as part of a collaboration between the University of Texas and PLAXIS BV.UNSPECIFIED
References
Abu-Hejleh, N. M., O’Neill, M. W., Hanneman, D., and Attwooll, W. J. (2003). “Improvement of the geotechnical axial design methodology for Colorado’s drilled shafts socketed in weak rocks.” CDOT-DTD-R-2003-6, Dept. of Transportation, Denver.
Aurora, R. P., and Reese, L. C. (1976). “Behavior of axially loaded drilled shafts in clay-shales.” Rep. No. 176-4, Center for Highway Research, Univ. of Texas at Austin, Austin, Tex.
Botts, M. E. (1986). “The effects of slaking on the engineering behavior of clay shales.” Doctoral dissertation, Civil Engineering, Univ. of Colorado, Boulder, Colo.
Briaud, J. L., and Lim, Y. (1999). “Tieback walls in sand: Numerical simulation and design implications.” J. Geotech. Geoenviron. Eng., 125(2), 101–110.
Dick, J. C., and Shakoor, A., eds. (1997). The locations and engineering characteristics of weak rock in the US, Association of Engineering Geologist, Denver.
Gökceoğlu, C., Ulusay, R., and Sönmez, H. (2000). “Factors affecting the durability of selected weak and clay-bearing rocks from Turkey, with particular emphasis on the influence of the number of drying and wetting cycles.” Eng. Geol. (Amsterdam), 57, 215–237.
Hassan, K. (1994). “Analysis and design of drilled shafts socketed into soft rock.” Doctoral dissertation, Dept. of Civil Engineering, Univ. of Houston, Houston.
Hassan, K. M., O’Neill, M. W., and Sheikh, S. A. (1997). “Design method for drilled shafts in soft argillaceous rock.” J. Geotech. Geoenviron. Eng., 123, 272–280.
Marques, E. A. G., Vargas, E. D. A., and Antunes, F. S. (2005). “A study of the durability of some shales, mudrocks and siltstones from Brazil.” Geotech. Geologic. Eng., 23(3), 321–348.
Nam, M. (2004). “Improved design for drilled shafts in rock.” Doctoral dissertation, Dept. of Civil Engineering, Univ. of Houston, Houston.
O’Neill, M. W., and Reese, L. C. (1999). “Drilled shafts: Construction procedures and design methods.” FHWA Publication No. FHWA-IF-99-025, Dept. of Transportation, Federal Highway Administration, McLean, Va.
PLAXIS manual; version 8. (2002). Balkema, Rotterdam, The Netherlands.
Raibagkar, A. (2008). “Simulation of concrete flow into verification core hole at the bottom of drilled shafts.” Master thesis, Dept. of Civil Engineering, Univ. of Texas at Austin, Austin, Tex.
Rowe, R. K., and Armitage, H. H. (1987). “A design method for drilled piers in soft rock.” Can. Geotech. J., 24(1), 126–142.
Sellountou, E. A. (2004). “The effects of construction on the behavior of augered-cast-in-place (ACIP) piles in Texas Gulf Coast soil.” Doctoral dissertation, Dept. of Civil and Environmental Engineering, Univ. of Houston, Houston.
TxDOT. (2004). Standard specifications for construction and maintenance of highways, streets, and bridges, Austin, Tex.
TxDOT. (2006). Geotechnical manual, Austin, Tex.
Vipulanandan, C., Hussain, A., and Usluogulari, O. (2007). “Parametric study of open core-hole on the behavior of drilled shafts socketed in soft rock.” GeoDenver 2007, ASCE, Reston, Va.
Youn, H. (2008). “Effect of verification core hole on the point bearing capacity of drilled shafts.” Doctoral dissertation, Dept. of Civil Engineering, Univ. of Texas at Austin, Austin, Tex.
Youn, H., and Weaver, T. J. (2006). “Influence of laterally loaded pile foundation on sheet pile wall.” Transportation Research Board 85th Annual Meeting, TRB, Washington, D.C.
Information & Authors
Information
Published In
Journal of Geotechnical and Geoenvironmental Engineering
Volume 136 • Issue 9 • September 2010
Pages: 1287 - 1297
Copyright
© 2010 ASCE.
History
Received: May 29, 2009
Accepted: Jan 29, 2010
Published online: Feb 8, 2010
Published in print: Sep 2010
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.