臺北盆地土壤液化潛勢分析

Analysis of Soil Liquefaction Potential for Taipei Basin

高哲豪(Che-Hao-Kao)

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(2020年)

https://doi.org/10.6846/TKU.2020.00121

摘要

臺北盆地屬國內政經發展之重心所在，又位於較弱、深厚之沖積地盤上，若發生震度夠大、延時夠長之地震，將可能發生土壤液化災害，使得人民財產與生命安全及建物等受到損害。本研究乃針對臺北盆地海拔二十公尺以下之範圍進行液化損害評估，以619筆鑽探孔位資料，進行JRA(1996)法、T-Y(1983)法與Seed(2001)法之確值法液化潛能評估，求出液化潛能指數PL、液化機率指數Pw及液化後沉陷量St，再以Towhata et al.(2016)提出之非液化土層厚度判定方法，分析臺北盆地之液化潛能趨勢。並利用克利金插值法(Kriging)、逐步高斯模擬法(SGS)及貝氏最大熵法(BME)等三方法進行地質統計推估，建構出臺北盆地液化損害參數之分佈圖，最後再據以分析臺北盆地可抽水深度及捷運沿線之液化損害潛勢。三種地質統計方法之分析結果趨勢皆大致相同，都以淡水河流域、基隆河流域及大漢溪流域兩岸之液化潛勢較高，工程規劃與設計上應謹慎評估土壤液化之災害影響，並採取適當之因應對策，以避免或降低土壤液化災害對地盤與結構物可能產生之不利影響。

關鍵字

臺北盆地 ； 土壤液化 ； 克利金法 ； 逐步高斯模擬法 ； 貝氏最大熵法

並列摘要

Taipei Basin is the political and economic center of Taiwan. The geological structure inside the basin consists of Quaternary layers above the Tertiary base rock. The surficial ground is mainly composed of unconsolidated soft soils with potential geological hazard to soil liquefaction. It is of substantial importance, therefore, to evaluate the damage hazard of infrastructure located at areas vulnerable to liquefaction in the basin. In this study, liquefaction potential are evaluated by using three common used method of JRA (1996), TY (1983) and Seed (2001) for 619 sites. Three damage indices of liquefaction are adopted. It is liquefaction potential index (PL), liquefaction probability index (PW) and liquefaction-induced settlement (St). On the other hand, the method proposed by Towhata et al. (2016) is also included, where the thickness of non-liquefied soil layers is considered to analyze the liquefaction potential. The maps of potential hazard for soil liquefaction and associated settlement in Taipei Basin are prepared by three geostatistics method, i.e. the Kriging method, Gaussian simulation method (SGS) and Bayesian maximum entropy method (BME). The pumpable depth of groundwater and the liquefaction potential along the MRT are also explored. According the analysis results, the liquefaction potential of the Tamsui river basin, the Keelung river basin and the Dahanxi river basin is relatively high. Thus, the impact of soil liquefaction on Taipei Basin should be carefully evaluated in engineering planning and design, and appropriate countermeasures should be taken to avoid or reduce the damage hazard of infrastructure when soil liquefaction is expected to happen.

並列關鍵字

Taipei Basin ； Soil liquefaction ； Kriging ； Stepwise Gaussian simulation ； Bayesian maximum entropy

參考文獻

參考文獻

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