土壤剪力波速經驗式與其不確定性之率定－基隆河與淡水河岸沖積場址案例研究

CALIBRATION OF EMPIRICAL FORMULAS OF SHEAR WAVE VELOCITY AND THEIR UNCERTAINTIES - A CASE STUDY IN ALLUVIUM SITES ALONG KEELUNG AND TAMSUI RIVER

王俊翔(Jiun-Shiang Wang) ； 黃俊鴻(Jin-Hung Hwang) ； 盧志杰(Chih-Chieh Lu) ； 鄧源昌(Yuan-Chang Deng)

《中國土木水利工程學刊》 35卷2期 (2023/04) Pp. 119-130

https://doi.org/10.6652/JoCICHE.202304_35(2).0002

摘要

土壤剪力波速（V_s）為重要之地工設計參數，雖以現地震測方法直接量測為最佳，但實務上因經濟考量，常以經驗式估計剪力波速，用於耐震地盤分類，因此經驗式之準確性相當重要。本研究蒐集整理臺北盆地13個同時具有跨孔震測、SPT與CPTU試驗之基隆河與淡水河岸沖積土層場址，所得之高品質試驗資料。首先進行資料的分類，初步探討剪力波速與土層深度，SPT與CPTU相關參數之相關性，繼則以此資料檢驗各種既有代表性經驗公式之適用性，結果顯示剪力波速與SPT-N及CPTU-q_c之相關性不高，與土層深度相關性較高，耐震規範之既有經驗公式並不適用。故本研究採用上述資料，重新迴歸各種準確度較高之剪力波速經驗公式，並以統計估計理論量化這些經驗公式之不確定性。所建議之經驗公式可供工程設計者參考，對應之不確定性模型與參數，可供可靠度分析應用。

關鍵字

剪力波速 ； 標準貫入試驗 ； 圓錐貫入試驗 ； 臺北盆地沖積層

並列摘要

Soil shear wave velocity (V_s) is an important parameter for geotechnical engineering design. The in-situ seismic test is the best method to measure it directly. In practice, due to economic considerations, and empirical formulas suggested in the seismic codes and literatures are often used to estimate the shear wave velocity for seismic site classification. Therefore, the accuracy of the empirical formula is very important. This research collects the high quality data from 13 alluvium sites along Keelung and Tamsui River in Taipei Basin with cross-hole seismic survey, SPT and CPTU tests at the same site. First, this study classifies the data, and discuss the correlations between shear wave velocity and soil depth, SPT and CPTU related parameters. After that, this database is exploited to test the applicability of various existing representative empirical formulas. The results show that V_s is not highly correlated with SPT-N and CPTU-q_c, whereas highly correlated with the depth of the soil layer. The existing empirical formula of the seismic code seems not applicable. Therefore, this study uses the above data to regress various empirical formulas of shear wave velocity with higher accuracy, and uses statistical estimation to quantify the uncertainty of these formulas. The suggested formulas can be used as reference for designers, and the corresponding uncertainty models and parameters can be used for reliability analysis applications.

並列關鍵字

shear wave velocity ； standard penetration tests (SPT) ； piezocone penetration tests (CPTU) ； alluvium of Taipei basin

參考文獻

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