颱風波浪下現地海床孔隙水壓激發及液化潛能評估

Liquefaction Potential Evaluation and Pore Pressure Buildup under Typhoon Waves Loading

簡連貴(Lien-Kwei Chien) ； 曾文謙(Wen-Chien Tseng) ； 陳保慶(Bao-Ching Chen)

《海洋工程學刊》 13卷4期 (2013/12) Pp. 349-365

https://doi.org/10.6266/JCOE.2013.1304.04

摘要

本研究利用高雄港洲際貨櫃中心為研究區域，配合地震與海洋波浪條件進行探討。採用高雄港洲際貨櫃中心外海水深為23.5 m之鑽探土樣為試驗土樣，並收集實測颱風波浪資料及考量地震力作用進行試驗，以期瞭解現地海床土壤受地震與波浪作用下之液化潛能及穩定性。為瞭解不同外力作用下海床土壤強度變化之真實情形，本研究採用現地海床土壤，利用過水霣降法方式進行製作試體，以模擬海床土壤深度z = 3 m沉積排列情形。同時利用自行發展建立動力三軸試驗系統模擬地震力以及波浪力結合扭剪應力進行試驗，採用Seed et al.（1976）及Chang（2004）孔隙水壓激發模式，研析孔隙水壓激發情形與現地海床土壤抗液化門檻值，並以Chen and Yang（1996）之評估方法為基礎，結合現地波浪參數建立簡易海床土壤液化潛能評估方法。由研究分析結果發現，若考量波浪力施加扭剪應力作用下，Seed et al. (1976) 孔隙水壓激發模式整體激發趨勢較相符合。本研究建議地震力可以以反覆作用次數Nc = 100（次）時之現地海床抗液化門檻值約0.19；波浪力以反覆作用時間1,200秒時之現地海床抗液化門檻值約0.20，做為高雄海域現地海床抗液化門檻值。以Chen and Yang（1996）之評估方法為基礎，建立之不同海床深度波浪作用下土壤剪應力比關係圖，求得此處最大可能液化深度為海床表面下4.57 m。利用本研究建立海床土壤液化潛能評估方法，可評估不同海床之深度受波浪力作用下是否可能發生海床液化破壞。

關鍵字

海床土壤 ； 動力三軸 ； 颱風波浪力 ； 孔隙水壓 ； 液化潛能評估

並列摘要

In this study, the Kaohsiung harbor intercontinental container center is adopted for the study area with seismic and ocean wave conditions to explore. The testing sample was obtained from the depth 23.5 m drilling seabed soil of the center of the coast of Kaohsiung intercontinental container. By use of the period of seismic force and the field of wave monitoring data, a series of the related dynamic testing were performed to understand the sea-bed soil liquefaction potential and stability under seismic and wave loading action. In order to understand the different external force of the sea bed soil strength changes in the real situation, this study uses the seabed soil test and prepare the specimen by the pluviation through water to simulate the deposition arranged in the case of sea-bed soil depth z = 3 m. Using the cyclic triaxial test system developed by this study to simulate the seismic forces and wave forces combined with the torsional shear stress test. The pore pressure model of Seed (1976) and Chang (2004) were adopted to evaluate the seabed soil pore water pressure mechanism and liquefaction resistance threshold. Based on the assessment method by Chen and Yang (1996) and combined with in-situ wave parameters, the assessment method of simplified liquefaction potential was established. From the test results indicated that it could be found Seed (1976) mode may be obtained more agree prediction of pore water pressure under different experimental conditions. This study suggests that the anti-liquefaction threshold value is about 0.19 by seismic force which can be adopted the number of cycles Nc is = 100 (times). And liquefaction resistance threshold value is about 0.20 by wave forces when the time of cyclic action is 1,200 seconds. Based on Chen and Yang (1996) assessment methods, and can establish the soil shear stress diagram with different depth of the seabed under wave action. The maximum possible the depth of liquefaction beneath the surface of the sea-bed is about 4.57 m. By use of the seabed soil liquefaction potential assessment method in study can assess the depth of the seabed by the wave force under the seabed liquefaction damage may occur.

並列關鍵字

seabed soil ； triaxial cyclic testing system ； typhoon wave loading ； pore water pressure ； liquefaction potential evaluation