Analysis of Cyclic Loading Transferred Mechanism on Geosynthetic-Reinforced and Pile-Supported Embankment

Sung-Jee Lee; Min-Tae Yoo; Su-Hyung Lee; Min-Cheol Baek; Il-Wha Lee

doi:10.7843/kgs.2016.32.12.79

All Issue

2016 Vol.32, Issue 12 Preview Page

Analysis of Cyclic Loading Transferred Mechanism on Geosynthetic-Reinforced and Pile-Supported Embankment 토목섬유로 보강된 성토지지말뚝 시스템의 반복하중 전이 메커니즘 분석

31 December 2016. pp. 79-91

PDF XML

Abstract

Geosynthetic-reinforced and Pile-supported (GRPS) embankment method is widely used to construct structures on soft ground due to restraining residual settlement and their rapid construction. However, effect of cyclic loading has not been established although some countries suggest design methods through many studies. In this paper, cyclic loading tests were conducted to analyze dynamic load transfer characteristics of pile-supported embankment reinforced with geosynthetics. A series of 3 case full scale model tests which were non-reinforced, one-layer-reinforced, two-layer reinforced with geosynthetics were performed on piled embankments. In these series of tests, the height of embankment and pile spacing were selected according to EBGEO (2010) standard in Germany. As a result of the vertical load parts on the pile and on the geosynthetic reinforcement measured separately, cyclic loads transferred by only arching effect decreased with strength geosynthetic-reinforced case. However, final loads on the pile showed no differences among the cases. These results conflict with previous studies which showed that reinforcement with geosynthetics increases transfer load concentrated on piles. In addition, it is observed that the load transferred to pile decreases at the beginning of cycle number due to reduction of arching effected by cyclic loading. Based on these results, transferred mechanism for cyclic load on GRPS system has been presented.

Keywords

GRPS embankment

Cyclic loading

Arching effect

Geosynthetic

Transferred load

토목섬유를 보강한 성토지지말뚝(GRPS) 공법은 연약지반 상부에 건설되는 성토구조물의 잔류침하를 억제하고, 공사기간을 단축할 수 있는 방법으로 그 적용성이 확대되고 있다. 이에, 세계 각국에서는 다양한 연구를 통해 설계방법을 제안해왔지만, 동적하중을 고려한 시스템의 거동은 확실하게 규명되지 않은 실정이다. 본 논문에서는 섬유보강 지지말뚝 성토체내의 동적하중 전이 특성을 분석하기 위하여 실물크기의 시스템을 조성한 후, 반복재하 실험을 수행하였다. 실험은 토목섬유를 설치하지 않은 무보강, 토목섬유를 1겹 설치한 보강, 2겹 설치한 보강을 조건으로 총 3 가지 경우로 나누어 진행하였다. 말뚝과 토목섬유 상부에 각각 하중계를 설치하여 반복재하 횟수에 따른 수직하중을 측정한 결과, 토목섬유의 보강효과를 제외하고 아칭효과에 의해서만 전이되는 반복하중은 오히려 인장력이 큰 토목섬유로 보강할수록 감소하는 경향이 나타났다. 그러나 최종 말뚝으로 전달되는 반복하중의 크기는 토목섬유를 보강하지 않은 경우와 1겹, 2겹 보강한 경우에서 모두 비슷한 것으로 평가되었다. 이는 토목섬유의 보강이 말뚝으로 집중되는 하중을 증가시킨다는 기존의 연구와는 상반된 결과로, 이를 바탕으로 반복하중 전이 메커니즘의 상관관계를 분석하고자한다 또한, 반복하중 재하 초기 말뚝으로의 하중전달 효과가 감소하는 경향이 보였으며, 이는 반복하중에 의한 아칭효과 감소에서 기인한 것으로 판단된다.

References

References

1.Arulrajah, Abdullah, Bo and Leong (2013), “Geosynthetic Applications in High-speed Railways: A Case Study”, Institution of Civil Engineers Ground Improvement, Volume 168, Issue 1, pp.3-13.

2.Barchard, J. M. (2002), Centrifuge Modelling of Piled Embankments on Soft Soils, M.S.C.E Thesis, Dept. of Civil Engineering, University of New Brunswick, Fredericton, New Brunswick, Canada.

3.BS8006-1 (2010), “Code of Practice for Strengthened/reinforced Soils and Other Fills”, British Standards Institution, ISBN 978-0- 580-53842-1.

4.Chen, Y. M., Cao, W. P., and Chen, R. P. (2008), “An Experimental Investigation of Soil Arching Within Basal Reinforced and Unrein-forced Piled Embankments”, Geotextiles and Geomembranes, Volume 26, Issue 2, pp.164-174.

5.CUR 226 (2010), “Ontwerprichtlijn Paalmatrassystemen (Design Guideline Piled Embankments)”, ISBN 978-90-376-0518-1 (in Dutch).

6.EBGEO (2010), “Empfehlungen für den Entwurf und die Berechnung von Erdkörpern mit Bewehrungen aus Geokunststoffen e EBGEO”, vol. 2. German Geotechnical Society, Auflage, ISBN 978-3-433- 02950-3 (in German). Also available in English: “Recommendations for Design and Analysis of Earth Structures using Geosynthetic Reinforcements EBGEO”, 2011. ISBN 978-3-433-02983-1 and digital in English ISBN 978-3-433-60093-1.

7.Hewlett, W. J. and Randolph, M. F. (1988), “Analysis of Piled Embankments”, Ground Engineering, April 1988, Volume 22, Number 3, pp.12-18.

8.Huat, B. B. K., Craig, W. H., and Ali, F. H. (1994), “The Mechanics of Piled Embankment”, FHWA International Conference on Design and Construction of Deep Foundations. Orlando. Florida, USA. Vol.2, pp.1069-1082.

9.Han, J. and Gabr, M. A. (2002), “Numerical Analysis of Geosynthetic- reinforced and Pile-supported Earth Platforms Over Soft Soil”, Journal of Geotechnical and Geoenvironmental Engineering, Volume 128, Issue 1, pp.44-53.10.1061/(ASCE)1090-0241(2002)128:1(44)

10.Han, J. and Bhandari, A. (2009), “Evaluation of Geogrid-reinforcedpile- supported Embankments under Cyclic Loading using Discrete Element Method”, Proc., U.S.–China Workshop on Ground Improvement Technologies, ASCE Geotechnical Special Publication, No.188, J. Han, G. Zheng, V. R. Schaefer and M. Huang, eds., ASCE, Orlando, FL, Reston, VA, pp.73-82.

11.Heitz, C. (2006), “Bodengewölbe unter Ruhender und Nichtruhender Belastung bei Berücksichtigung von Bewehrungseinlagen aus Geogittern. Schriftenreihe Geotechnik”, University of Kassel, Issue 19, November 2006 (in German).

12.Heitz, C., Lüking, J., and Kempfert, H.-G. (2008), “Geosynthetic Reinforced and Pile Supported Embankments under Static and Cyclic Loading”, Proceedings of the 4th European Geosynthetics Conference EuroGeo 4, Edinburgh (United Kingdom).

13.Hong, W. P. and Lee, G. W. (2003), “Model Tests on Embankment Piles with Isolated Pile Caps”, Journal of the Korean geotechnical society, Vol.19, No.6, pp.49-59.

14.Hong, W. P. and Lee, G. W. (2007), “Soil Arching in Embarikments Suppoyed by Piles with Geosynthethics”, Journal of the Korean geotechnical society, Vol.23, No.6, pp.53-66.

15.Iglesia, G. R., Einstein, H. H., and Whitman, R. V. (1999), “Determination of Vertical Loading on Underground Structures based on an Arching Evolution Concept”, Fernandez G, Bauer RA (eds) Proc. 3rd Nat. Conf. Geo-Engng for Underground Facilities. Geotechnical Special Publication (GSP) 90, pp.495-506. Reston, VA, USA: ASCE

16.Jones, C. J. F. P., Lawson, C. R., and Ayres, D. J. (1990), “Geotextile Reinforced Piled Embankments”, Proceedings of 5th International Conference on Geotextiles, Geomembranes and Related Products, Vol.1, pp.155-160.

17.Kempfert, H. G., Gobel, C., Alexiew, D., and Heitz, C. (2004), “German Recommendations for Reinforced Embankments on Pilesimilar Elements”, paper presented to Proc., 3rd European Geosynthetic conference, Deutsche Gesell schaft fur Geotechnik, Munich, Germany.

18.Low, B. K., Tang, S. K., and Chao, V. (1994), “Arching in Piled Embankments”, Journal of Geotechnical Engineering, Volume 120, Issue 11, pp.1917-1938.10.1061/(ASCE)0733-9410(1994)120:11(1917)

19.Lee, G. W. (2006), Design method of the geosynthetic-reinforced and pile-supported embankment system to control lateral flow in soft grounds, PhD.Thesis, University of Chung-Ang.

20.Lee, S. H. (2009), “Numerical Study on the Effects of Geosynthetic Reinforcement on the Pile-supported Embankment”, Journal of Korean Society for Railway, Vol.12, No.2, pp.276-284.

21.Lodder, H. J., van Eekelen, S. J. M., and Bezuijen, A. (2012), “The Influence of Subsoil Reaction in a Basal Reinforced Piled Embank-ment”, Proceedings of Eurogeo5, Valencia. Volume 5.

22.Lee, K. W., Jung, S. G., Kim, U. G. and Cho, S. D. (2014), “Tudy on the Suitability of Geosynthetics to Reinforce Embankment Piles”, 2014 Korean society of civil Engineers Conference

23.Magnan, J. P. (1994), “Methods to Reduce the Settlement of Embank-ments on Soft Clay: A Review”, In Vertical and Horizontal Deformations of Foundations and Embankments, ASCE Geotechnical Special Publication No.40, Vol.1, pp.77-91.

24.Moormann, C., J. Lehn, J., and Aschrafi, J. (2016), “DESIGN OF REINFORCED PILED EARTH STRUCTURES UNDER STATIC AND VARIABLE LOADS”, Geo Americas 2016 3rd Pan-American Conference on Geosynthetics, April 2016, pp.10-13.

25.Shen, S. L., Chai, J. C., Hong, Z. S., and Cai, F. X. (2005), “Analysis of Field Performance of Embankments on Soft Clay Deposit with and Without PVD-improvement”, Geotextiles and Geomembranes, Volume 23, Issue 6, pp.463-485.10.1016/j.geotexmem.2005.05.002

26.Terzaghi, K. (1943), Theoretical Soil Mechanics, John Wiley and Sons, New York.10.1002/9780470172766

27.Van Eekelen, S.J.M. and Bezuijen, A. (2012), “Basal Reinforced Piled Embankments in the Netherlands, Field Studies and Laboratory Tests”, proceedings of ISSMGE-TC 211 International Symposium on Ground Improvement IS-GI, Brussels.

28.Zaeske, D. (2001), “Zur Wirkungsweise von Unbewehrten und bewehrten Mineralischen Tragschichten über Pfahlartigen Gründung-selementen”, Schriftenreihe Geotechnik, Uni Kassel, Heft 10, February 2001 (in German).

Information

Publisher :The Korean Geotechnical Society
Publisher(Ko) :한국지반공학회
Journal Title :Journal of the Korean Geotechnical Society
Journal Title(Ko) :한국지반공학회 논문집
Volume : 32
No :12
Pages :79-91
Received Date : 2016-10-11
Revised Date : 2016-11-03
Accepted Date : 2016-11-11
DOI :https://doi.org/10.7843/kgs.2016.32.12.79

Journal of the Korean Geotechnical Society ISSN:1229-2427(Print) 2288-646X(Online) 한국지반공학회 논문집

All Issue

References