台灣近年積極推動離岸風電發展，執行多個離岸風場之地質調查，目前離岸海床地質調查主要以圓錐貫入試驗 (CPT) 為主。圓錐貫入試驗可以穩定速率量測連續性之參數，並可確定土壤行為類型和預估土壤參數。離岸大口徑單樁長度可達百米，若依據CPT各數據點土壤分類後劃分土層，土層數可達數百層，導致垂直承載力之計算複雜且無效率，因此需使用地層分層方法簡化土層數，然而，不同土層結果會影響垂直承載力計算結果，因此，本研究將探討不同土層分層對離岸基樁垂直承載力之影響。本研究分析三孔CPT數據資料，依據 Robertson (2009) 土壤分類圖進行土壤分類，採用三種不同的地層分層方法簡化土層數—T檢定統計量法、移動平均法和WTMM法，並比較各方法分層結果和鑽孔取樣判釋結果之吻合度；後續選擇各方法吻合度最高之分層結果進行垂直承載力分析，垂直承載力採用API RP 2A (2014), NGI-05, ICP-05, Fugro-04, UWA-05五種方法計算。結果顯示，T檢定統計量法、移動平均法和WTMM法三種地層分層方法皆和鑽探結果吻合度佳且無使用特定地層分層方法會造成垂直承載力數值較大或較小的情形，三種方法均可使用；而基於CPT結果計算離岸基樁垂直承載力之四種方法中，使用Fugro-04最不保守，而使用NGI-05則最為保守。

The study focuses on the influence of soil layering on vertical bearing capacity of offshore pile. The content of paper can be divided into three parts. The first part is classifying soil behavior type and calculating the soil parameters, The second part is simplifying the soil layers by three soil layering methods —T-ratio method, moving average method, WTMM (wavelet transform modulus maxima) method and comparing the degree of similarity between the results of three soil laying methods and the interpretation results of drilling samples. The last part is calculating the vertical bearing capacity by four CPT-based methods and comparing the results of different soil layers and the difference between the four methods.
The results show that three soil layering methods are all in good agreement with the drilling results. Among the four CPT-based methods for calculating the vertical bearing capacity of offshore piles, Fugro-04 is the least conservative method, and NGI-05 is the most conservative method.

1. American Petroleum Institute (API), “Recommended Practice for Planning, Designing, and Constructing Fixed Offshore Platforms – Working Stress Design,” Report RP 2A-WSD, Twenty Second Edition, (2014).
2. Baldi, G., Bellotti, R., Ghionna, N., and Jamiolkowski, M., “Stiffness of sands from CPT, SPT and DMT—A critical review.” Proceedings of the PeneT-ration Testing in the UK, London, pp. 299-305 (1989).
3. Begemann, H., “The friction jacket cone as an aid in determining the soil profile.” Proceedings of the 6th International Conference on SMFE, Vol. 1, pp. 17-20 (1965).
4. Cetin, K. O., and Ozan, C., “CPT-based probabilistic soil characterization and classification.” Journal of Geotechnical Geoenvironmental Engineering, Vol. 135, No. 1, pp. 84-107 (2009).
5. Ching, J., Wang, J.-S., Juang, C. H., and Ku, C.-S., “Cone peneT-ration test (CPT)-based stratigraphic profiling using the wavelet transform modulus maxima method.” Canadian Geotechnical Journal, Vol. 52, No. 12, pp. 1993-2007 (2015).
6. Chow, F., “Investigations into displacement pile behaviour for offshore foundations.” Ph.D. Thesis (1997).
7. Clausen, C., Aas, P., and Karlsrud, K., “Bearing capacity of driven piles in sand, the NGI approach.” Proceedings of the International Symposium on Frontiers in Offshore Geotechnics (2005).
8. Douglas, B., and Olsen, R., “Soil classificaion using electric cone penetrometer.” Proceedings of the Symp. on Cone PeneT-ration Testing and Experience, Geotech. Engrg. Div., pp. 209-227 (1981).
9. Fenton, G. A., “Random field modeling of CPT data.” Journal of Geotechnical Geoenvironmental Engineering, Vol. 125, No. 6, p. 486 (1999).
10. Jardine, R., Chow, F., Overy, R., and Standing, J., ICP Design Methods for Driven Piles in Sands and Clays, Thomas Telford London (2005).
11. Jefferies, M., and Been, K., Soil Liquefaction: A Critical State Approach, CRC Press (2006).
12. Jefferies, M., and Davies, M. P., “Use of CPTU to estimate equivalent SPT N 60.” Geotechnical Testing Journal, Vol. 16, No. 4, pp. 458-468 (1993).
13. Jia, J., Soil Dynamics and Foundation Modeling, Springer (2018).
14. Karlsrud, K., Clausen, C., and Aas, P., “Bearing capacity of driven piles in clay, the NGI approach.” Proceedings of the Proc. Int. Symp. on frontiers in offshore geotechnics, Vol. 1, pp. 775-782 (2005).
15. Lehane, B. M., Jardine, R., Bond, A. J., and Frank, R., “Mechanisms of shaft friction in sand from instrumented pile tests.” Journal of Geotechnical Engineering, Vol. 119, No. 1, pp. 19-35 (1993).
16. Lehane, B. M., Schneider, J., and Xu, X., A Review of Design Methods for Offshore Driven Piles in Siliceous Sand, The University of Western Australia (2005a).
17. Lehane, B. M., Schneider, J., and Xu, X., “The UWA-05 method for prediction of axial capacity of driven piles in sand.” Proceedings of the International Symposium on Frontiers in Offshore Geotechnics, pp. 683-689 (2005b).
18. Lengkeek, H., De Greef, J., and Joosten, S., CPT Based Unit Weight Estimation Extended to Soft Organic Soils and Peat, CRC Press (2018).
19. Lunne, T., Powell, J. J., and Robertson, P. K., Cone PeneT-ration Testing in Geotechnical Practice, CRC Press (1997).
20. Mayne, P., and Peuchen, J., “CPTu bearing factor Nkt for undrained strength evaluation in clays.” Proceedings of the Fourth International Symposium on Cone PeneT-ration Testing (CPT 2018) Conference, At Delft (2018).
21. Mayne, P. W., “Generalized CPT method for evaluating yield stress in soils.” Proceedings of the Geo-Congress 2014: Geo-Characterization and Modeling for Sustainability, pp. 1336-1346 (2014).
22. Robertson, P. K., “Estimating in-situ state parameter and friction angle in sandy soils from CPT.” Proceedings of the 2nd International Symposium on Cone PeneT-ration Testing, Huntington Beach, CA, USA (2010a).
23. Robertson, P. K., “Interpretation of cone peneT-ration tests—a unified approach.” Canadian Geotechnical Journal, Vol. 46, No. 11, pp. 1337-1355 (2009).
24. Robertson, P. K., “Interpretation of in-situ tests–some insights.” Mitchell Lecture-ISC, Vol. 4, pp. 1-22 (2012).
25. Robertson, P. K., “Soil behaviour type from the CPT: an update.” Proceedings of the 2nd International Symposium on Cone PeneT-ration Testing, Vol. 2, p. 8 (2010b).
26. Robertson, P. K., “Soil classification using the cone peneT-ration test.” Canadian Geotechnical Journal, Vol. 27, No. 1, pp. 151-158 (1990).
27. Robertson, P. K., and Cabal, K., “Estimating soil unit weight from CPT.” Proceedings of the 2nd International Symposium on Cone PeneT-ration Testing, pp. 2-40 (2010).
28. Robertson, P. K., and Cabal, K., Guide to Cone PeneT-ration Teating for Geotechnical Engineering, Gregg Drilling & Testing, Inc. (2015).
29. Robertson, P. K., Campanella, R. G., Gillespie, D., and Greig, J., “Use of piezometer cone data.” Proceedings of the Use of in Situ Tests in Geotechnical Engineering, pp. 1263-1280 (1986).
30. Robertson, P. K., and Wride, C., “Evaluating cyclic liquefaction potential using the cone peneT-ration test.” Canadian Geotechnical Journal, Vol. 35, No. 3, pp. 442-459 (1998).
31. Schneider, J. A., Randolph, M. F., Mayne, P. W., and Ramsey, N. R., “Analysis of factors influencing soil classification using normalized piezocone tip resistance and pore pressure parameters.” Journal of Geotechnical Geoenvironmental Engineering, Vol. 134, No. 11, pp. 1569-1586 (2008).
32. Wickremesinghe, D. S., “Statistical characterization of soil profiles using in situ tests.” Ph.D. Thesis, University of British Columbia (1989).
33. Xu, X., Schneider, J. A., and Lehane, B. M., “Cone peneT-ration test (CPT) methods for end-bearing assessment of open-and closed-ended driven piles in siliceous sand.” Canadian Geotechnical Journal, Vol. 45, No. 8, pp. 1130-1141 (2008).
34. Yu, F., and Yang, J., “Base capacity of open-ended steel pipe piles in sand.” Journal of Geotechnical Geoenvironmental Engineering, Vol. 138, No. 9, pp. 1116-1128 (2012).
35. Zhang, G., Robertson, P., and Brachman, R. W., “Estimating liquefaction-induced ground settlements from CPT for level ground.” Canadian Geotechnical Journal, Vol. 39, No. 5, pp. 1168-1180 (2002).
36. 王俊翔，「根據圓錐貫入試驗資料判識土壤層面與分析工址的機率特性」，碩士論文，國立臺灣大學土木工程學研究所，台北市 (2016)。