| 摘要(英) |
Site effect plays an important role in issues of strong ground motion studies. Site effect is caused by soft deposits overlaying hard rock, causing seismic ground motions to be amplified and increasing damage during large earthquake. The time-averaged shear-wave velocity in the upper 30 meters, i.e. VS30, is the most popular and widely be used site parameters representing the site effect in engineering seismology. In this case, VS30 can be estimated based on void ratio and effective vertical stress by transformation functions with data within 30 meters. An extrapolation method:Conditional Independent Property (CIP) model by (Dai et al., 2013) is applied when available data is less than 30 meters. The data of soil physical property data and wave velocity measurements from the Engineering Geological Database for TSMIP (EGDT) were collected and checked, we then proposed transformation functions to predict the shear-wave velocity (VS) using void ratio and effective vertical stress based on the database from 2000 to 2008. Using both transformation functions and extrapolation method, the VS at each depth from numerous drilling boreholes from Central Geological Survey (CGS) has been estimated to obtain VS30 for each borehole. Finally, Kinging with varying local means is used to create a distribution map of VS30 in the Taipei Basin.
Based on regression analysis for sand, silt and clay in the Taipei Basin with EGDT data from 2000 to 2008, resulting in improved RMSE values compared with (Kuo, 2021) have results such as Transformation function for Sand: RMSE from 45.8 m/s decrease of 30.8 m/s and transformation function for Silt and Clay: RMSE from 47.9 m/s decrease to 29.2 m/s. In addition, by separating clay and silt, we have two transformation function better than combined with RMSE 26.52 m/s and 29.86 m/s, So three transformation functions estimate VS30 for CGS boreholes: Sand, Silt, Clay.
The number of boreholes for (Kuo, 2021) result is about 1914 boreholes, and this study updated to 5773 boreholes, include equal to or larger than 30m and less than 30 meters for Kriging with varying local means.
Overall, according to the study, the VS30 distribution in the Taipei Basin ranges from approximately 157 m/s to 640 m/s. Based on this distribution, three specific areas can be identified:North, Northeast, and Southwest Areas: These areas have VS30 values less than 210 m/s.South to East Margin of the Taipei Basin: This area has VS30 values larger than 300 m/s. Center of the Taipei Basin: The VS30 values in this area range from 210 to 300 m/s.
This study found that areas with VS30 values less than 210 m/s in the Taipei Basin exhibit higher accuracy compared to (Kuo, 2021) results and suggests that incorporating additional data in these regions has improved the prediction of VS30 value. In addition, in North, Northeast and Center of Taipei Basin, this research provides less residuals values of VS30 comparing with (Kuo, 2021)
Keywords: VS30, void ratio, effective stress, Taipei Basin, site effect, CIP model |
| 參考文獻 |
Chen, C. T., Kuo, C. H., Lin, C. M., Huang, J. Y., and Wen, K. L. . (2022). Investigation of shallow S-wave velocity structure and site response parameters in Taiwan by using high-density microtremor measurements. Engineering Geology, 297, 106498.
Dai, Z. L. (2013). A shear‐wave velocity model for VS30 estimation based on a conditional independence property. Bulletin of the Seismological Society of America, 103(6), 3354-3361.
Diehl, J. (2001). GEOVision P-S Log Notes & Procedures.
Kawase, H., Lee, W. H. K., Kanamori, H., Jennings, P. C., and Kisslinger, C. (2003). Site effects on strong ground motions. International Geophysics Series 81.B, 81.B,1013-1030.
Kuo, C. H., Wen, K. L., Hsieh, H. H., Chang, T. M., Lin, C. M., and Chen, C. T. (2011a). Evaluating empirical regression equations for Vs and estimating Vs30 in northeastern Taiwan. Soil Dynamics and Earthquake Engineering, 31(3), 431-439.
Kuo, C. H., Wen, K. L., Hsieh, H. H., Lin, C. M., and Chang, T. M. (2011b). Characteristics of Near-Surface S-wave Velocity. The National Center for Research on Earthquake Engineering(NCREE), NCREE-11-022.
Kuo, C. H., Wen, K. L., Hsieh, H. H., Lin, C. M., Chang, T. M., and Kuo, K. W. (2012). Site classification and Vs30 estimation of free-field TSMIP stations using the logging data of EGDT. Engineering Geology, 129, 68-75.
Kuo, C.L. (2021). Correlation between shear wave velocity, void ratio and effective stress: Mapping Vs30 in Taipei Basin. National Central University, Master Thesis in Chinese.
Lee C.T., Huang T.M., Liao C.W, and Chen H..J. (2002). The contruction and application of a subsurface geologic database system - An example from the Taipei Basin. Sino-Geotechnics, No.89, p.13-26.
Lee, C.T., and Tsai, B.R. (2008). Mapping Vs30 in Taiwan. Terrestrial, Atmospheric and Oceanic Sciences, 19(6), 617-682.
Robertson, P. K., Sasitharan, S., Cunning, J. C., and Sego, D. C. (1995). Shear-wave velocity to evaluate in-situ state of ottawa sand . Journal of Geotechnical Engineering divison, 121(3), 262-273.
Building Seismic Safety Council (BSSC) of the National Insititute of Building. (2020). NEHRP recommended seismic provisions for new buildings and other structures(FEMA P-2082-1). Washington, DC.
Tsai, B.R. (2007). Further Study for Site Classification of Taiwan Free-Field Strong-Motion Station. National Central Univerity, Master Thesis in Chinese.
Xie, J., Zimmaro, P., Li, X., Wen, Z., and Song, Y. (2016). VS 30 empirical prediction relationships based on a new soil‐profile database for the Beijing plain area, China. Bulletin of the Seismological Society of America, 106(6), 2843-2854.
Lin, Y.C. (2023), 以孔隙比、有效應力與剪力波速關係繪製臺北盆地 Vs30 分布圖, National Central Univerity, Master Thesis in Chinese. |
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