Instrumented Static Load Test on Rock-Socketed Micropile
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VIEW THE REPLYPublication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 139, Issue 12
Abstract
Rock-socketed piles are often used to transfer heavy loads from a superstructure to competent underlying rock layers. The loads are transferred by the pile to the surrounding rock mass through shaft and base resistance. Several researchers have investigated the behavior of rock-socketed drilled shafts and related the uniaxial compressive strength of intact rock to pile-shaft resistance. However, the load-transfer behavior and load-settlement response of micropiles are different from those of drilled shafts because of the large slenderness ratio () of micropiles. This study presents results from a fully instrumented field-scale load test on a 0.2-m-diameter micropile socketed 4.2 m into limestone layers (2.7 m into weathered limestone and 1.5 m into hard limestone). The results show that practically no base resistance is mobilized until the pile-head settlement reaches approximately 7% of the diameter of the test micropile. The measured limit shaft resistance values are compared with values predicted using methods available in the literature. The comparison indicates that use of the intact strength of the rock for estimation of limit shaft resistance may lead to an unconservative design when the rock mass quality is very poor, as indicated by, for example, low rock-quality designation values.
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References
AASHTO. (1996). Standard specification for highway bridges, 16th Ed., Washington, DC.
Bica, A., Prezzi, M., Seo, H., Salgado, R., and Kim, D. (2013). “Instrumentation and axial load testing of displacement piles.” Proc., ICE–Geotechnical Engineering, Institution of Civil Engineers (ICE), Thomas Telford, London, in press.
Carter, J. P., and Kulhawy, F. H. (1988). “Analysis and design of drilled shaft foundations socketed into rock.” Rep. No. EPRI EL-5918, Electrical Power Research Institute, Palo Alto, CA.
Coates, D. F. (1967). Rock mechanics principles, Queen's Printer, Ottawa.
Federal Highway Administration (FHWA). (1999) ‘‘Drilled shafts: Construction procedures and design methods.’’ Rep. No. FHWA-IF-99-025, U.S. Dept. of Transportation, McLean, VA.
Federal Highway Administration (FHWA). (2000). “Micropile design and construction guidelines—Implementation manual.” Rep. No. FHWA-SA-97-070, U.S. Dept. of Transportation, McLean, VA.
Federal Highway Administration (FHWA). (2010). ‘‘Drilled shafts: Construction procedures and LRFD design methods.’’ Publication No. FHWA-NHI-10-016, FHWA GEC 010, U.S. Dept. of Transportation, McLean, VA.
Finno, R. J. (2002). “Evaluation of capacity of micropiles embedded in dolomite.” Final Rep. Infrastructure Technology Institute, Northwestern Univ., Evanston, IL.
Gómez, J., Cadden, A., and Bruce, D. A. (2003). “Micropiles founded in rock: Development and evolution of bond stresses under repeated loading.” Proc., 12th Pan-American Conf. on Soil Mechanics and Geotechnical Engineering (Soil Rock America 2003), VGE, Essen, Germany, 1911–1916.
Horvath, R. G., and Kenney, T. C. (1980). “Shaft resistance of rock-socketed drilled piers.” Proc., Symp. Deep Foundations, ASCE, Reston, VA, 182–214.
Horvath, R. G., Kenney, T. C., and Kozicki, P. (1983). “Method of improving the performance of drilled piers in weak rock.” Can. Geotech. J., 20(4), 758–772.
Kim, D., Bica, A. V. D., Salgado, R., Prezzi, M., and Lee, W. (2009). “Behavior of a closed-ended pipe pile driven in mixed soil.” J. Geotech. Geoenviron. Eng., 135(4), 463–473.
Kulhawy, F. H., and Phoon, K. (1993). “Drilled shaft side resistance in clay soil to rock.” Proc., Geotechnical Special Publication No. 38, ASCE, Reston, VA, 172–183.
Leong, E. C., and Randolph, M. F. (1994). “Finite element modeling of rock-socketed piles.” Int. J. Numer. Anal. Methods Geomech., 18(1), 25–47.
Le Tirant, P. (1992). Design guides for offshore structures: Offshore pile design. Association de Recherche en Geotechnique Marine, Paris.
Massoudi, N. (2004). “Rock socketed micropiles.” Proc., GeoSupport Conf. 2004, GeoSupport 2004: Drilled Shafts, Micropiling, Deep Mixing, Remedial Methods, and Specialty Foundation Systems (GSP 124),ASCE, Reston, VA, 175–185.
Mylonakis, G. (2001). “Winkler modulus for axially loaded piles.” Geotechnique, 51(5), 455–461.
Paik, K., Salgado, R., Lee, J., and Kim, B. (2003). “Behavior of open- and closed-ended piles driven into sands.” J. Geotech. Geoenviron. Eng., 129(4), 296–306.
Pells, P. J. N., and Turner, R. M. (1979). “Elastic solutions for the design and analysis of rock-socketed piles.” Can. Geotech. J., 16(3), 481–487.
Poulos, H. G. (1982). “The influence of shaft length on pile load capacity in clays.” Geotechnique, 32(2), 145–148.
Randolph, M. F. (1983). “Discussion of ‘The influence of shaft length on pile load capacity in clays’.” Geotechnique, 33(1), 75–76.
Randolph, M. F., and Wroth, C. P. (1978). “Analysis of deformation of vertically loaded piles.” J. Geotech. Engrg. Div., 104(GT12), 1465–1488.
Rosenberg, P., and Journeaux, N. L. (1976). “Friction and bearing tests on bedrock for high capacity socket design.” Can. Geotech. J., 13(3), 324–333.
Rowe, R. K., and Armitage, H. H. (1987). “A design method for drilled piers in soft rock.” Can. Geotech. J., 24(1), 126–142.
Salgado, R. (2008). The engineering of foundations, 1st Ed., McGraw Hill, New York.
Sandford, T. C., McCarthy, J., and Bussiere, J. (2011). “Development of supplemental resistance method for the design of drilled shaft rock sockets.” Rep. No. NETCR83, Final report submitted to New England Transportation Consortium, Univ. of Maine, Orono, ME.
Seo, H., Basu, D., Prezzi, M., and Salgado, R. (2009a). “Load-settlement response of rectangular and circular piles in multilayered soil.” J. Geotech. Geoenviron. Eng., 135(3), 420–430.
Seo, H., and Prezzi, M. (2008). “Use of micropiles for foundations of transportation structures.” Final Rep., Publication FHWA/IN/JTRP-2008/18, Joint Transportation Research Program, Indiana Department of Transportation and Purdue Univ., West Lafayette, IN.
Seo, H., Yildirim, I. Z., and Prezzi, M. (2009b). “Assessment of the axial load response of an H pile driven in multi-layered soil.” J. Geotech. Geoenviron. Eng., 135(12), 1789–1804.
Seol, H.-I., and Jeong, S.-S. (2007). “Shaft resistance characteristics of rock-socketed drilled shafts based on pile load tests.” J. Korean Geotech. Soc., 23(9), 51–63.
Serrano, A., and Olalla, C. (2004). “Shaft resistance of a pile embedded in rock.” Int. J. Rock Mech. Min. Sci., 41(1), 21–35.
Shatnawi, E. S. (2008). “Development of p-y criterion for anisotropic rock and cohesive intermediate geomaterials.” Ph.D. dissertation, Univ. of Akron, Akron, OH.
Williams, A. F., and Pells, P. J. N. (1981). “Side resistance of rock sockets in sandstone, mudstone, and shale.” Can. Geotech. J., 18(4), 502–513.
Zhang, L. (1999). “Analysis and design of drilled shafts in rock.” Ph.D. dissertation, Massachusetts Institute of Technology (MIT), Cambridge, MA.
Zhang, L., and Einstein, H. H. (1998). “End bearing capacity of drilled shafts in rock.” J. Geotech. Geoenviron. Eng., 124(7), 574–584.
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© 2013 American Society of Civil Engineers.
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Received: Jan 9, 2012
Accepted: Apr 11, 2013
Published online: Apr 13, 2013
Published in print: Dec 1, 2013
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