本研究透過數值模擬並搭配波傳理論探討基樁打擊時應力波在樁間的傳遞情況，同時連結土壤阻抗對樁頭質點速度的影響，以現場監測技術和樁體與土層互制嘗試建立實務可行之滑樁預警架構。研究以數值模型並視樁為一彈性體，使用不同勁度的土壤藉由控制不同的樁土界面強度及勁度，來模擬高樁周阻抗及顯著樁尖位移等情況下的波傳反應，對應現地動態打樁分析儀(Pile Dynamic Analyzer, PDA)之感測器所量測的位置，觀察數值模型受力及質點速度歷時的波型變化。模擬結果顯示樁底土壤勁度上升時，回彈波的相角變化並不顯著，但樁周阻抗上升時，在回彈波到達之前，受力與質點速度波型隨時間分離的程度愈大，且回彈波的振幅會因土壤阻抗下降而上升，因此透過量化兩波型分離程度，建立一樁周阻抗評估指標，並將不同種類土壤與分層納入考量，結合樁載重試驗模擬求得之樁極限承載力，可驗證評估指標之合理性，打樁數值模型結果顯示，在不同樁土界面強度及勁度的情況下，模型樁評估指標與極限承載力近乎呈線性相關，藉以提出滑樁預警之架構。

This study utilizes numerical simulation and wave propagation theory to observe the stress wave propagation behavior during pile driving, while considering the influence of pile head particle velocity due to soil resistance. Attempt to establish a warning framework for pile running by techniques of field monitoring and considering the pile-soil interaction. The research employs numerical models treating the pile as an elastic body and varying the soil stiffness and strength to simulate wave propagation behavior under high pile-soil resistance and significant pile tip displacement conditions. To observe the changes in force and particle velocity waveforms over time in numerical models, corresponding to the positions measured by sensors of the Pile Dynamic Analyzer (PDA) during pile driving. The simulation results indicate that when the stiffness of the soil under the pile tip increases, there is no significant change in the phase angle of the rebound wave. However, with increasing pile-soil resistance, the separation between the force and particle velocity waveforms before the arrival of the pile tip rebound wave becomes more pronounced. On the other hand, the amplitude of the pile tip rebound wave increases due to the decreasing soil resistance. To establish an evaluation Index for pile-soil resistance by quantifying the waveform separation, and taking different types of soil and stratification into consideration. Using the results of ultimate bearing capacity from pile loading test simulation to validate the rationality of this index. The analysis results show that the evaluation index is nearly linearly correlated with the ultimate bearing capacity of pile under different pile-soil interface strengths and stiffness, providing a framework for pile running warning.

1. Bowles, J. E. (1988). Foundation analysis and design. New York, McGraw-Hill Publishing.
2. Butler, H. D. and Hoy, H. E. (1977) Users manual for the texas quick-load method for foundation load testing. Federal Highway Adminstration, Office of Development, Washington.
3. Byrne, B. (2011). Foundation Design for Offshore Wind Turbines. Géotechnique Lecture, University of Oxford, 5.
4. Das, B. M. (2016). Principles of Geotechnical Engineering(8th ed.). Stamford, Cengage Learning Publishing.
5. Davisson, M. T. (1972). High Capacity Piles. In Proceedings of the Lecture Series on Innovations in Foundation Construction., ASCE, Illinois Section, Chicago, 81-112.
6. De Beer, E. E. (1967). Proefondervindlijke bijdrage tot de studie van het grensdraag vermogen van zand onder funderingen op staal. Tijdshift der Openbar Verken van Belgie, 6.
7. Fuller, R. M. and Hoy, H. E. (1970). Pile load tests including quick-load test method, conventional methods and interpretations, HRB, 333.
8. Goble, G. G. and Rausche, F. (1980). Pile drivability predictions by CAPWAP. Numerical methods in offshore piling. Thomas Telford Publishing. 29-36.
9. Goble, G. G., Raushe, F., and Likins, G. E. (1980). The analysis of pile driving-a state-of-the-art. In Proceedings of the International Seminar on the Application of Stress-wave Theory to Piles, Stockholm, 131-161.
10. Hardin, B. O. (1978). The nature of stress-strain behaviour for soils. In Proceedings of Geotechnical Division Specialty Conference on Earthquake Engineering and Soil Dynamics, ASCE, 3-90.
11. Holden, J. C. (1991). History of the first six CRB calibration chambers. Proceedings, First International Symposium on Calibration Chamber Testing, Potsdam, New York, editor, Huang, A. B., Elsevier, New York, 1-12.
12. Huang, A. B. and Hsu, H. H. (2005). Cone Penetration Tests under Simulated Field Conditions. Géotechnique, 55(5), 345-354.
13. Lysmer, J.,and Kuhlmeyer, R. L. (1969). Finite dynamic model for infinite media. Journal of Soil Mechanics and Foundations Division, ASCE, 95(4), 859-878.
14. Mabsout, M. E., Reese, L. C. and Tassoulas, J. L. (1995). Study of pile driving by finite-element method. Journal of Geotechnical Engineering, 121(7), 535-543.
15. Ohta, Y., and Goto, N. (1978). Empirical shear wave velocity equations in terms of characteristic soil indexes. Earthquake engineering and structural dynamics, 6(2), 167-187.
16. Plaxis b. v. (2019). Plaxis 2D version2019, reference manual, Delft, Netherlands.
17. Rausche, F., Goble, G. G. and Likins, G. E. (1985). Dynamic determination of pile capacity. Journal of Geotechnical Engineering, 111(3), 367-383.
18. Richart, F. E., Hall, J. R. and Woods, R. D. (1970). Vibrations of soils and foundations.
19. Skempton, A. W. (1957). Discussion of" The planning and design of the new Hong Kong Air Port". Proceedings of the Institution of Civil Engineers, 7, 305-307.
20. Skempton, A. W., and Jones, O. T. (1944). Notes on the compressibility of clays. Quarterly Journal of the Geological Society, 100(1-4), 119-135.
21. Smith, E. A. L. (1960). Pile-driving analysis by the wave equation. Journal of Soil Mechanics and Foundations Division, 86(4), 35-61.
22. Sun, L., Jia, T., Yan, S., Guo, W., Ren, Y. and Lei, Z. (2016). Prediction of pile running during the driving process of large diameter pipe piles. Ocean Engineering, 128, 48-57.
23. Terzaghi, K. (1942). Discussion of the progress report of the committee on the bearing value of pile foundation. Proc. ASCE, 68.
24. Terzaghi, K., Peck, R. B., and Mesri, G. (1996). Soil mechanics in engineering practice. John wiley & sons Publishing.
25. Vucetic, M., and Dobry, R. (1991). Effect of soil plasticity on cyclic response. Journal of geotechnical engineering, 117(1), 89-107.