Journal of the Korean GEO-environmental Society (한국지반환경공학회 논문집)

Korean Geo-Environmental Society (한국지반환경공학회)
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The Effect of Dynamic Behavior on Changing Pile Cap Size of Pile Group in Sandy Soil

사질토 지반에서 말뚝 캡 크기가 무리말뚝의 동적거동에 미치는 영향

  • Lee, Hyunkun (Osong Enterprise Organization, Chungbuk Development Corporation) ;
  • Ahn, Kwangkuk (School of Civil Engineering, Chungbuk National University) ;
  • Kang, Hongsig (R & D Department, Byeokdong Construction Co. Ltd.)
  • Received : 2019.05.20
  • Accepted : 2019.07.26
  • Published : 2019.08.01
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Abstract

A pile group, that consists of several piles connected by a pile cap, is used as the superstructure. The pile supports vertical and horizontal load to design the pile group, but the effect of bearing capacity of the pile cap has not considered. Various researches have been conducted to reflect the effect of bearing capacity of the pile cap in order to reduce the amount of piles in the range of the stability under the vertical load of the superstructure. However, the effect of bearing capacity under the horizontal seismic load has not been studied adequately. Therefore, a shaking table test was carried out with different-sized pile caps that support the superstructure in this study. This test was to verify the influence of the size of the pile cap in the group pile under the horizontal load. The result shows that the size of the pile cap affects to the dynamic behavior of the superstructure and the pile group. Also, the bigger size of the pile group makes the larger constraint effect of ground, and it results that both the ground and the pile moves as a whole.

상부구조물은 여러 개의 말뚝 기초를 말뚝 캡으로 연결한 무리말뚝이 사용되고 있다. 무리말뚝 설계 시 상부구조물의 연직 및 수평하중은 말뚝 기초가 지지할 뿐 말뚝 캡의 지지효과는 무시하였다. 그러나 최근 상부구조물의 연직하중에 대한 안정성 범위에서 말뚝 기초의 사용량을 줄이기 위해 말뚝 캡의 지지효과를 반영하기 위한 연구가 진행되고 있으나 수평하중에 대한 말뚝 캡의 지지효과에 관한 연구는 미비한 실정이다. 이에 본 연구에서는 수평 지진 하중을 받는 무리말뚝에서 말뚝 캡의 변화가 무리말뚝에 미치는 영향을 확인하기 위해 상부구조물을 지지하는 무리말뚝의 말뚝 캡 크기를 변화시켜 진동대 모형실험을 수행하였다. 그 결과 말뚝 캡의 크기가 상부구조물 및 무리말뚝의 동적 거동에 영향을 미치는 것으로 확인되었으며, 말뚝 캡의 크기가 증가할수록 지반 구속 효과로 인해 지반과 말뚝 기초가 일체 거동하는 것으로 나타났다.

Keywords

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Fig. 1. Shaking table device

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Fig. 2. Model box

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Fig. 3. Superstructure

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Fig. 4. Pile group

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Fig. 5. Ofunato earthquake

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Fig. 6. Measuring instrument

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Fig. 7. Altering dynamic p-y curve

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Fig. 8. Acceleration of ground (7.5 cm)

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Fig. 9. Acceleration of pile cap

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Fig. 10. Acceleration of superstructure

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Fig. 11. Frequence of superstructure

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Fig. 12. Dynamic p-y curve (LP, 7.5 cm)

Table 1. Jumunjin standard sand

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References

  1. Ahn, K. K. (2003), Pile-soil-pile interaction in pile groups under lateral loading, Ph D. dissertation, Illinois Tech, Chicago, USA, pp. 280-282.
  2. Bao, N. N., Nghiem, X. T. and Kim, S. R. (2018), Evaluation of dynamic p-y curves of group piles using centrifuge model tests, Journal of the Korean Geotechnical Society, Vol. 34, No. 5, pp. 53-63 (In Korean). https://doi.org/10.7843/KGS.2018.34.5.53
  3. Cho, J. Y., Jeong, S. S. and Lee, J. H. (2013), Development of three-dimensional interactive analysis for superstructure-piled raft foundation, Journal of korean Geotechnical Society, Vol. 29, No. 6, pp. 19-31. https://doi.org/10.7843/kgs.2013.29.6.19
  4. Iiba, M., Tamori, S. and Kitagawa, Y. (2003), Fundamental characteristics on seismic effect to pile foundation by shaking table test for model of building-soil interaction system, J.Struct. Constr.Eng, Japanese, 566, pp. 29-36.
  5. Katzenbach, R., Schmitt, A. and Turek, J. (2005), Assessing settlement of high-rise structures by 3D simulations, Computer-Aided Civil and Infrastructure Engineering, 20, pp. 221-229. https://doi.org/10.1111/j.1467-8667.2005.00389.x
  6. Kim, S. h., Ahn, K. K. and Kang, H. S. (2018), Dynamic behavior of group piles according to pile cap embedded in sandy ground, Journal of the Korean Geo-Environmental Society, Vol. 19, No. 10, pp. 35-41.
  7. Mandolini, A., Russo, G. and Viggiani, C. (2005), Piled foundations: Experimental I nvestigations, analysis and design, Stateof-the-Art Rep. Proc., 16th ICSMGE, Osaka, Japan, Vol. 1, pp. 177-213.
  8. Reul, O. and Randolph, M. F. (2003), Piled rafts in overconsolidated clay-Comparison of in-situ measurements and numerical analyses, Geotechnique, Vol. 53, No. 3, pp. 301-315. https://doi.org/10.1680/geot.2003.53.3.301
  9. Shirato, M., Nonomura, Y., Fukui, J. and Nakatani, S. (2008), Large-scale shaking table experiment and numerical simulation on the nonlinear behavior of pile-groups subjected to large-scale earthquakes. Journal of Soils and Foundations. the japanese geotcehnical society, Vol. 48, No. 3, pp. 375-396. https://doi.org/10.3208/sandf.48.375
  10. Suzuki, H., Tokimatsu, K. and Tabata K. (2014), Factors affecting stress distribution of a $3{\times}3$ pile group in dry sand based on three-dimensional large shaking table tests, Journal of Soils and Foundations, the japanese Geotechnical Society, Vol. 54, No. 4, pp. 699-712. https://doi.org/10.1016/j.sandf.2014.06.009
  11. Tabata, K. and Sato, M. (2006), Report of Special Project for Earthquake Disaster Mitigation in Urban Areas. Ministry of Education, Culture, Sports Science and Technology, Japanese, pp. 489-554.
  12. Tokimatsu, K., Suzuki, H., Sato, M. and Tabata, K. (2007), Three-dimensional shaking table tests on soil-pile-structure models using E-Defense facility. In: Proceedings of 4th International Conference on Earthquake Geotechnical Engineering, 11pp.
  13. Yang, E. K., Yoo, M. T., Kim. H. U. and Kim, M. M. (2009), Dynamic p-y backbone curves for a pile in saturated sand, Journal of the Korean Geotechnical Society, Vol. 25, No. 11, pp. 27-38 (In Korean).
  14. Yoo, M. T., Choi, J. I., Han, J. T. and Kim, M. M. (2013), Dynamic p-y curves for dry sand by dynamic centrifuge tests, Journal of Earthquake Engineering, Vol. 17, No. 7, pp. 1082- 1102 (In Korean). https://doi.org/10.1080/13632469.2013.801377