Foundation can be subjected to additional load and constructed in soft soils; therefore, the settlement or foundation tilting is achieved. The most beneficial method to control the settlement and foundation tilting are to be used Micro-piles which have been considered is an effective and easy to reinforce the existing foundation, it also successfully adopted in many ground improvement techniques to safeguard structure from collapse. The paper aims to study the behavior of full-scale micro piles under compression in the filed with length of 20 m as end bearing with diameter of 88.9 mm. This study is focused on the observing the behavior of three micro-piles installed with different technique. The first is normal one without injection as pipe piles MP1, the second is pipe pile with grouted bulb MP2 only under the toe of micro-piles and inside grouting. The last one or third micro-pile MP3 is pipe pile with fully injection for both toe and around the pile length. Three loading tests in the field are carried out to show the load settlement response under axial compression and horizontal load to get the ultimate micro-pile capacity. The results showed that the fully injected micro-piles with grouting have a higher ultimate load capacity and minor settlement compared with other two cases. The ultimate load capacities for fully grouted micro-piles and only with grouted bulb are found to be 13 and 8 times of ultimate capacity of pipe micro-piles without grouted bulb at the toe respectively. Also, it is found that the ultimate horizontal load capacity of Mp3 is found to be 27 ton while it is recorded as 3 and 4 ton for MP1 and MP3 respectively at horizontal displacement of 0.2 micro-pile diameter.
T. Armour, “Micropile Design and Construction Guidelines Implementation Manual” FHWA Federal Highway Administration Priority Technologies Program (PTP) Project 6, June, 2000.
D.A Bruce, A. F. DiMillio, and E.G. Juran, “Micropiles: The state of Practice Part 2: Design of single micropiles and groups and networks of Micropiles” - Ground improvement, Thomas Telford, Vol.2, 1997.
M. R. Ziaie and S.A. Naeini “Improvement of loose sandy soil deposits using micropiles”. KSCE Journal of Civil Engineering 16(3): 334–340.2012.
K. Larsson and D. Jog “Performance of micropiles used to underpin highway bridges”. Journal of Performance of Constructed Facilities ASCE 28(3): 592–607.2014.
I. Juran, A. Benslimane and D.A Bruce Slope stabilization by micropile reinforcement. Landslides 5: 1718–1726.1996.
M. L. Lin, K.L. Wang, “Seismic slope behavior in a large-scale shaking table model test”. Eng. Geol. 86 (2–3), 118–133.2006.
C. Choi, S-D. Cho, J. Goo, J. Jeoung, K-H. Lee, J-H. Lee, “Foundation construction method of micro pile using pack used in the same, Korea Patent No.10-2008-0034653. 2008.
C. Choi, J-M. Goo, J-H Lee, and S-D Cho, "Development of New Micropiling Method Enhancing Frictional Resistance with Geotextile Pack", Proceeding of ISM 9th Workshop on Micropiles 2009, London, May 2009.
FHWA, “Micro-pile Design and Construction. United States Department of Transportation”, No. FHWA NHI-05-039, December, pp. 5-1–5-18.2005.
T. Hwang, K. Kim, and H. Shin, “Effective installation of micropiles to enhance bearing capacity of micropiled raft. Soils and Foundations” ,Volume 57, Issue 1, Pages 36-49, , February 2017.
W. R. Azzam, and A.M Basha, "Utilization of micro-piles for improving the sub‑grade under the existing strip foundation: experimental and numerical study", Innovative Infrastructure Solutions (2018) 3:44, 2018.
J. Han, and S.L. Ye, “A field study on the behavior of a foundation underpinned by micro-piles”. Can. Geotech. J. 43 (1), 30–42,2006.
Bellato, D’Agostini, Cola and Simonini “Behaviour of micropiles in heterogeneous coarse soils Proceedings of the Institution of Civil Engineers http://dx.doi.org/10.1680/jgeen.15.00069 pp:1-14, 2015.
G. Russo, “Full-scale load tests on instrumented micropiles”, Proceedings of the Institution of Civil Engineers – Geotechnical Engineering Volume 157 Issue 3, pp. 127-135, July 2004.
O. Nusier, A.S. Alawneh, and R. Rabadi, “ Micropiles reinforcement for expansive soils: large-scale experimental investigation” Proceedings of the Institution of Civil Engineers - Ground Improvement 2007 11:2, 55-60, 2007.
J.E. Gomez, C.J. Rodriguez, H.D. Robinson, J. Mikitka, and L/ Keough. “Hollow core bar micro-piles—installation, testing, and interpolation of design parameter of 260 micro-piles.” In Proceedings of the 8th International Workshop on Micropiles, Toronto, Ont., 22–26 September 2007. [CD-ROM].
L. Wen, G. Kong, Q. Li, and Z. Zhang, “Equivalent diameter of grouted micropile embedded in marine soft clay under lateral load” Proceedings of the Institution of Civil Engineers - Geotechnical Engineering 2020 173:1, 3-12, 2020.
T. Armour, P. Groneck, J. Keeley, S. Sharma “Micropile Design and Construction Guidelines. Implementation Manual. Federal Highway Administration, FHWA-SA-97-070., 1997.
ASTM (1994) – D1143-81 Standard Test Method for piles under static axial compressive load.
ASTM (1995) – D3689-90 Standard Test Method for individual piles under static axial tensile load.
D. Bellato, S. D’Agostini, and P. Simonini, “Interpretation of failure load tests on micropiles in heterogeneous Alpine soils” Rivista Italiana di Geotecnica, 1. pp.1-16, 2013
M.T Davisson, “High capacity piles. Proceedings, Lecture Series, Innovations in Foundation Construction”, ASCE, Illinois Section, 52 pp, 1972.
L. C. Reese, and M. W. O'Neill "Drilled Shaft, Student Workbook." Publication for FHWA-HI-88-042. FHWA, U.S. Department of Transportation, 1988.
F.K. CHIN, “Estimation of the ultimate load of piles not carried to failure”. Proc. 2nd Southeast Asian Conf. on Soil Engng., Singapore, pp. 81- 90, 1970.
P.J. Sabatini, B. Tanyu, T. Armour, P. Groneck and J. Keeley “Micropile Design and Construction – Reference Manual. Federal Highway Administration, Washington, DC, USA, FHWA-NHI-05-039, 2005.
Yueying Bian; Tara C. Hutchinson; Dan Wilson; Debra Laefer; and Scott Brandenberg “Experimental Investigation of Grouted Helical Piers for Use in Foundation Rehabilitation”. Journal of Geotechnical and Geoenvironmental Engineering .Volume 134 Issue 9 - September 2008.
B. Broms, “Lateral resistance of piles in cohesive soils,” Soil Mechanics and Foundations Division, vol. 90, pp. 27–63, 1964.
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