臺北盆地濱水區受震引致側向擴展變位之研究

Study on the Seismic-induced Lateral Spreading along the Waterfront for Taipei Basin

邵晨陽(Chen-Yang Shao)

指導教授 ： 黃富國

淡江大學/工學院/水資源及環境工程學系碩士班/碩士(2021年)

https://doi.org/10.6846/TKU.2021.00187

摘要

臺北盆地是臺灣重要的政經中心，又位於軟弱沖積地盤上，若受震引致土壤液化震害，勢必會對人民的生命財產造成很大的損害；對於濱水區附近微傾地盤，也可能引致側向擴展變位，而導致建築物、堤防護岸、維生管線，以及跨河橋梁等的震損，影響居住安全及地震時搶救災路線的通行。為防範液化及側向擴展災害之發生，本研究乃蒐集近年來臺北盆地中級液化潛勢圖資計畫之地質鑽孔及地下水位資料，以及淡水河系(淡水河、基隆河、新店溪)各河段斷面剖面圖，考慮耐震設計規範(設計地震、最大考量地震)及山腳斷層錯動(震矩規模7.1、7.5)二種境況、四種不同地震力，進行確值法之液化潛能評估與逐步高斯模擬空間推估，並採用Youd et al.(2002)所建議之多元線性迴歸MLR方法，從事各河段濱水區場址之側向擴展變位分析。另外，也根據聯合國減災組織UNDRO (1979)之定義，結合危害度及脆弱度分析，進行各濱水區及跨河橋梁場址之側向擴展變位的風險分析，評估結果可做為臺北盆地液化及側向擴展變位等相關防災工作參考。
分析結果顯示，山腳斷層錯動引致的側向擴展風險，大於耐震設計規範地震情境下之風險。因此，評估側向擴展變位震害時，宜將特徵地震震源山腳斷層之影響，納入分析考慮。就山腳斷層錯動而言，淡水河濱水場址因液化而發生側向擴展之風險最高、基隆河次之、新店溪風險最小。在濱水區附近風險較大場址之建築物、堤防護岸等土工設施、維生管線及橋梁基礎等，須特別做好防範及補強措施，以避免土壤液化及側向擴展變位可能引致之震害!

關鍵字

臺北盆地 ； 土壤液化 ； 側向擴展 ； 逐步高斯模擬法 ； 風險分析

並列摘要

Taipei Basin, the political and economic center of Taiwan, is underlain by soft alluvium soils that may be susceptible to soil liquefaction and the hazard of lateral spreading along the waterfront with sloping ground under earthquake strike. It is of substantial importance, therefore, to evaluate the damage hazard and risk of the infrastructure located at areas vulnerable to liquefaction and lateral spreading in the basin. The data of boring log, ground water table, and cross section along each river (Tamsui River, Keelung River, and Xindian River) in Taipei Basin are collected first. Two possible earthquake scenarios with four different intensities according to aseismic design code (including design earthquake and maximum considered earthquake) and the rupture of Shanchiao Fault (including moment magnitude of 7.1 and 7.5) are considered. The spatial damage index of liquefaction is interpolated by the method of Sequential Gaussian simulation. The multilinear regression (MLR) model published by Youd et al.(2002) is used to evaluated the displacement of lateral spreading. And then, the approach suggested by UNDRO (1979) that combines the hazard and vulnerability is used to evaluate the risk of lateral spreading along the waterfront and the sites of bridge.
It is shown that the risk of lateral spreading induced by the rupture of Shanchiao Fault is greater than those from design earthquake and maximum considered earthquake of aseismic design code. The influence of characteristic earthquake of Shanchiao Fault on the lateral spreading displacement is the most important, and thus it is need to be included for estimating the risk. In the scenario of rupture of Shanchiao Fault, the risks of lateral spreading adjacent to the sites near the bank of Tamsui River are the largest, with Xindian River being the smallest. Thus, if the sites of building, bridge, earthworks, and lifeline are located along those waterfronts with high risk, the countermeasures against soil liquefaction and lateral spreading must be made to avoid the associated damages when earthquake occurs.

並列關鍵字

Taipei Basin ； Soil liquefaction ； Lateral spreading ； Sequential Gaussian simulation ； Risk analysis

參考文獻

1.Andrus, R. D., and Stokoe II, K. H. (2000). “Liquefaction resistance of soils from shear-wave velocity,” Journal of Geotechnical and Geoenvironmental Engineering, ASCE, Vol. 126, No. 11, pp. 1015-1025.

2.Bartlett, S. F., and Youd, T. L. (1992). “Empirical analysis of horizontal ground displacement generated by liquefaction-induced lateral spreads,” Technical Rep. NCEER-92-0021, National Center for Earthquake Engineering Research, SUNY-Buffalo, Buffalo, NY,114–126.

3.Bartlett, S. F., and Youd, T. L. (1995). “Empirical prediction of liquefaction-induced lateral spread,” Journal of Geotechnical and Geoenvironmental Engineering. Vol. 121, No. 4, pp. 316-329.

4.Baziar, M. and Saeedi, A. (2013) “Evaluation of lateral spreading utilizing artificial neural network and genetic programming,” International Journal of Civil Engineering, Vol. 11, pp. 100–111.

5.Bardet, J-P., Mace, N., and Tobita, T. (1999) “Liquefaction-induced ground deformation and failure,” A Report to PEER/PG&E. Civil Engineering Department, University of Southern California, Los