STATIC ANALYSES OF THE EFFECT OF DEEP EXCAVATION ON THE BEHAVIOUR OF AN ADJACENT PILE IN SAND

Öz

The influence of deep excavation on adjacent pile behaviour is an important issue to ensure its serviceability and stability. In this paper, the effect of deep excavation on an adjacent loaded single pile in saturated cohesionless soil was investigated by 3D finite element method. After verification of finite element model using centrifuge test results found in literature, a parametric study was conducted by varying the most influence factors on the pile behaviour such as excavation depth, distance from the pile to the excavation and pile head type. It was concluded that the excavation depth (He) with respect to pile length (Lp) has a significant effect on pile response. Among the three cases of He/Lp, the case of He/Lp=0.5 induced the maximum bending moment while the case of He/Lp= 1.5 induced the maximum pile lateral deflection. Moreover, the distance from the pile to the excavation site has also a significant influence on pile response and the induced bending moment in pile is inconsiderable after 9 m distance. Also, it is observed that the pile head type has an important effect on the pile behaviour especially in case of rigid head case.

Anahtar Kelimeler

• deep excavation
• single pile
• finite element method
• sand

Kum Zemindeki Bir Derin Kazının Komşu Kazığın Davranışı Üzerindeki Etkisinin Statik Analizi

Öz

Bitişik kazık davranışı üzerindeki derin kazı etkisinin incelenmesi, kazığın hizmet verebilirliğini ve stabilitesini değerlendirmek için önemli bir konudur. Bu çalışmada, bitişik yüklü tekil kazık üzerindeki derin kazının etkisi, doymuş kohezyonsuz zeminde, 3D sonlu elemanlar yöntemi kullanılarak araştırılmıştır. Literatürde bulunan santrifüj deney sonuçları kullanılarak sonlu elemanlar modelinin doğrulanmasından sonra; kazı derinliği, kazıkla kazı alanına olan mesafe ve kazık başı tipi gibi kazık davranışına en fazla etki eden faktörler üzerinde parametrik bir çalışma yapılmıştır. Kazık uzunluğuna göre kazı derinliğinin kazık davranışı üzerinde önemli bir etkiye sahip olduğu sonucuna varılmıştır. Üç farklı He/Lp durumu arasında, He/Lp= 0.5 durumu maksimum eğilme momentine neden olurken, He/Lp= 1.5 durumu maksimum kazık yanal sapmasına neden olmuştur. Ayrıca kazıktan kazıya olan mesafe de kazık tepkisi üzerinde önemli bir etkiye sahiptir ve kazıkta aktive olan eğilme momenti 9 m mesafeden sonra etkisini kaybetmiştir. Son olarak kazık başlığı tipinin kazık davranışı üzerinde önemli bir etkisi olduğu görülmüştür, özellikle rijit başlık durumunda bu etkiler daha dikkat çekicidir.

Anahtar Kelimeler

• derin kazı
• tekil kazık
• kum zemin
• sonlu elemanlar yöntemi

Kaynakça

1. 1. ACI Committee 318. (2005) Buliding code requirements for structural concrete and commentary.
2. 2. Bolton, M.D. and Powrie, W. (1986) The collapse of diaphragm walls retaining clay, Geotechnique, 37(3), 335-353. doi:10.1680/geot.1987.37.3.335
3. 3. Choudhury, D., Shen, R.F., Leung, C.F. and Chow, Y.K. (2006) Centrifuge model study on pile responses due to adjacent excavation, ASCE Geoshanghai International Conference, Shanghai, 145–151. doi:10.1061/40865(197)18
4. 4. Ding, W., Qiao, Y. 2014. Numerical Analysis of Pile Response to Deep Excavation in Soil Overlying Rock., ASCE Geoshanghai 2014, 700–709. doi: 10.1061/9780784413449.068
5. 5. Goh, A.T.C., Wong, K.S., Teh, C.I., Wen, D. (2003) Pile response adjacent to braced excavation, J. Geotech. and Geoenvrion. Eng., ASCE, 129(4):383-396. doi:10.1061/(ASCE)1090-0241(2003)129:4(383)
6. 6. Finno, R.J., Laurence, S.A., Allauh N.F., Harahap I.S. (1991) Analysis of performance of pile groups adjacent to deep excavation, J. Geotech. Eng., ASCE, 117(6), 934-55. doi:10.1061/(ASCE)0733-9410(1991)117:6(934)
7. 7. Hsiung, B.C.B. (2009) A case study on the behaviour of a deep excavation in sand, Computers and Geotechnics, 36(4), 665-675. doi:10.1016/j.compgeo.2008.10.003
8. 8. Leung, C.F., Chow, Y.K., Shen, R.F. (2000) Behavior of pile subject to excavation-induced soil movement, J. Geotech. and Geoenvrion. Eng., ASCE, 126(11), 947–954. doi: 10.1061/(ASCE)1090- 0241(2000)126:11(947)

9. 9. Leung, C.F., Lim, J.K., Shen, R.F., Chow, Y.K. (2003) Behaviour of pile Groups subject to excavation-induced soil movement, J. Geotech. and Geoenvrion. Eng., ASCE, 129(1), 58-65. doi:10.1061/(ASCE)1090-0241(2003)129:1(58)
10. 10. Li, L., Hu, X., Dong, G., Liu, J. (2014) Three-Dimensional Numerical Analyses of Pile Response due to Braced Excavation-Induced Lateral Soil Movement, Applied Mechanics and Materials, 580-583:524-531. doi:10.4028/www.scientific.net/amm.580-583.524
11. 11. Liyanapathirana, D.S., Nishanthan, R. (2016) Influence of deep excavation induced ground movements on adjacent piles, Tunneling and Underground Space Technology, 52, 168–181. doi:10.1016/j.tust.2015.11.019
12. 12. Ng, C.W.W., Yau, T.L.Y., Li, J.H.M., Tang, W.H. (2001) New failure load criterion for large diameter bored piles in weathered geomaterials, J. Geotech. and Geoenvrion. Eng., ASCE, 127 (6), 488-498. doi:10.1061/(ASCE)1090-0241(2001)127:6(488)
13. 13. Ng, C.W.W., Wei, J., Poulos, H. and Liu, H. (2017) Effects of multipropped excavation on an adjacent floating pile. J. Geotech. and Geoenviron. Eng., ASCE, 143(7), 04017021. doi:10.1061/(ASCE)GT.1943-5606.0001696
14. 14. Nishanthan, R., Liyanapathirana, D.S., Leo, C.J. (2016) Shielding effect in pile groups adjacent to deep unbraced and braced excavations. Int. Journal of Geotech. Eng., 11(2):162-174. doi:10.1080/19386362.2016.1200270
15. 15. Ong, D.E., Leung, C.F., Chow, K.Y. (2006) Pile behavior due to excavation-induced soil movement in clay. I: Stable Wall, J. Geotech. Geoenviron. Eng., 132(1), 36-44. doi:10.1061/(ASCE)1090-0241(2006)132:1(36)
16. 16. Poulos, H.G., Chen, L.T. (1996) Pile response due to unsupported excavation-induced lateral soil movement, Canadian Geotech. Journal, 33(4): 670-677. doi:10.1139/cgj-33-4-670
17. 17. Poulos, H.G., Chen, L.T. (1997) Pile response due to excavation-induced lateral soil movement, J. Geotech. and Geoenviron. Eng., ASCE, 123(2):94-99. doi:10.1061/(ASCE)1090-0241(1997)123:2(94)
18. 18. PLAXIS Material Models CONNECT Edition V20.
19. 19. Soomro, M.A., Mangnejo, D.A., Bhanbhro, R., Memom, N.A. (2019) 3D finite element analysis of pile responses to adjacent excavation in soft clay: Effects of different excavation depths systems relative to a floating pile, J. Tunnelling and Underground Space Technology, 86, 138-155. doi:10.1016/j.tust.2019.01.012
20. 20. Shakeel, M. and Ng, C.W.W. (2017) Settlement and load transfer mechanism of pile group adjacent to a deep excavation in soft clay, Comput. Geotech., 96, 55-72. doi:10.1016/j.compgeo.2017.10.010
21. 21. Smulders, C.M., Hosseini, S., Brinkgreve, R.B.J. (2019) Improved embedded beam with interaction surface, Proceedings of the XVII ECSMGE 2019, Reykjavik, 1-8. doi:10.32075/17ECSMGE-2019-0139
22. 22. Teh, K.L., Leung, C.F., Chow, Y.K. (2005) Spudcan penetration in sand overlying clay, ISFOG 2005, Perth, Australia, 529-534.
23. 23. Ünsever, Y.S. (2015) An experimental study on static and dynamic behaviour of model pile foundations. PhD thesis, ODTÜ Fen Bilimleri Enstitüsü, İnşaat Müh. Anabilim Dalı, Ankara.
24. 24. Yamashita, S., Jamiolkowski, M., Presti, D. C. L. (2000) Stiffness nonlinearity of three sands, J. Geotech. Geoenviron. Eng., ASCE, 126(10),929-942. doi:10.1061/(ASCE)1090-0241(2000)126:10(929)
25. 25. Zhang, R., Zhang, W., Goh, A. (2018) Numerical investigation of pile responses caused by adjacent braced excavation in soft clays, Int. J. Of Geotech. Engineering., 1-15. doi:10.1080/19386362.2018.1515810