國內西南沿海填海造地之開發正逐漸展開，碼頭或海堤之背填土壤均為砂土，可能因強震造成背填土壤液化，而造成碼頭往外移動。本研究透過離心模型試驗資料之分析，來探討沉箱式碼頭地震時的受震反應，及對於可能產生背填土液化之碼頭提供一套合理的沉箱式碼頭側向位移之分析方法。 研究結果顯示，於受震反應部分，滲透係數愈低之土壤，土壤液化導致加速度震幅及剪力波速Vs降低之幅度愈顯著；受震期間，超額孔隙水壓上升後，整體勁度降低，沉箱基本震動模態會由高頻轉至低頻，對低頻的輸入運動較為敏感。且沉箱本身之水平震動模態、旋轉模態與地震記錄及沉箱與背填土間均存在著相差之關係，滲透係數愈低的土壤，水平震動模態、旋轉模態與地震紀錄之相差及沉箱與背填土間之相差愈大。 側向位移分析部分，本研究根據Siddharthan(1992)針對乾砂提出擋土牆之複合運動方程式作一修正，將水之影響在力平衡方程式中考慮。根據此種觀念推導動態平衡方程式，經程式計算結果與離心模型試驗結果及台中港現地災害案例做比較，有不錯的準確度，可提供業界在沉箱受震引致側向位移分析時的參考。 Land reclamation has been rapidly developed and heavy industry facilities are being constructed along southwestern coast of Taiwan. Structures such as quay walls, moles or bridge abutments may move seawards as a result of liquefaction of sand backfill behind retaining structure system during strong earthquake motion. The measured data of centrifuge model are used to analysis the response of a caisson type quay wall during liquefaction induced by a strong earthquake and a procedure for the determination of lateral displacement of caisson type quay wall is proposed. In this thesis, observed the relationship of phase shift, the reduction of acceleration amplitude and shear wave velocity resulted from liquefaction. Not only relationship of phase shifts between input motion and responses of the quay wall, including horizontal translation mode, rotation model and input base motion, but also that between the responses of the quay wall and the backfill are found. In addition, the fundamental frequency of the quay wall is reduced to a lower frequency due to the reduction of system stiffness resulted from the excess pore water pressure increased during vibration. The phenomenon is more apparent when the coefficient of permeability of soils is lower. Coupled equations of motion presented by Siddharthan al. (1992) were revised by considering the influence of water. A revised procedure for determination of lateral displacement of the quay wall will be proposed. The comparison of results between numerical analysis and centrifuge tests is well. The result of numerical analysis is closed to the hazard in Taichung Harbor. The methodology can be well applied to a caisson type quay wall design in engineering.
