黏性土坡耐震穩定性之離心機與數值模擬;Centrifuge Modelling and Numerical Simulation on Seismic Slope Stability of a Cohesive Embankment

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Title:	黏性土坡耐震穩定性之離心機與數值模擬;Centrifuge Modelling and Numerical Simulation on Seismic Slope Stability of a Cohesive Embankment
Authors:	黃俊鴻
Contributors:	土木工程學系
Keywords:	研究領域：土木水利工程類
Date:	2011-01-01
Issue Date:	2012-01-17 17:23:06 (UTC+8)
Publisher:	行政院國家科學委員會
Abstract:	黏性土坡耐震穩定性之離心機與數值模擬本計畫為申請台灣-印度雙邊科技合作計畫之一，主題為與地震工程相關之『黏性土坡耐震穩定性之離心機與數值模擬』，計畫為三年期，台灣方面計畫主持人為國立中央大學土木工程系之黃俊鴻教授，印度方面為印度國立技術學院(National Institute of technology) Silchar分校的Ashim Kanti Dey 教授。此研究之主要目的在評估黏性土坡受震之降服加速度與殘留位移，降服加速度被定義為使土坡產生明顯位移之最小擬靜態加速度。受震殘留位移則代表土坡受震穩定程度之指標。本研究計畫以動態離心機模擬黏性土坡在地震作用下之降服加速度與殘留位移。將準備不同稠度與含水量之黏性土坡模型，以簡諧與實際地震運動施加於離心振動台底部，於模型中裝設加速度計、水壓計與位移計量測土坡之動態與震後反應，並以網格標記錄下變形模態與滑動面位置。預期黏性土稠度與動態荷載扮演關鍵性之角色。黏土稠度將以不排水剪力強度、阿太保限度與自然含水量代表，地震荷載則以最大尖峰加速度與等價作用週數來表示。最後期望由試驗資料來建立黏土稠度、土坡幾何、地震荷載與降服加速度及殘留位移之關係。本研究也規劃以數值模擬方法補充試驗數量之不足，將以FLAC2D軟體模擬離心試驗結果，加以調整校正數值模型與參數，使其具有可性度後，再選擇台灣與印度的地震土坡破壞案例進行驗證。待所建立數值分析模型正確後，變化不同影響參數的範圍，進行大量的數值試驗，補強擴充黏土稠度、土坡幾何、地震荷載與降服加速度及殘留位移之關係。最後簡化精緻成簡單的設計圖表供工程師參考應用。 CENTRIFUGE MODELLING AND NUMERICAL SIMULATION ON SEISMIC SLOPE STABILITY OF A COHESIVE EMBANKMENT The main objective of the present study is to evaluate the yield acceleration and seismic residual deformation of a given slope made of clay. Yield acceleration is defined as the minimum pseudo-static acceleration required to produce a significant deformation of a slope. Seismic residual deformation is an index to represent the degree of embankment instability caused by seismic loading. This project plans to perform centrifuge modelling to study the yield acceleration and seismic residual deformation of a cohesive slope when subject to earthquake loading using the dynamic centrifuge. Different cohesive slope model will be prepared with clayey soils of different consistency. A number of real earthquake acceleration histories will be selected to be the input motions to shake the model slope. Dynamic responses of model slope will be monitored by arrays of accelerometers, piezometers, and LVDTs. Test procedure will be arranged to increase peak acceleration step by step to find out a minimum value beyond which the slope starts to deform significantly. The minimum value can be defined as yield acceleration. The deformation pattern and failure surface will be recorded by mesh mark. It is expected that the consistency of clayey soil plays an important role in slope stability. The dynamic stability also depends upon the earthquake intensity and duration. The intensity can be represented by a peak acceleration and the duration is denoted by an equivalent loading cycle. Thus an experimental relationship among permanent displacement, yield acceleration, consistency of clayey soil, slope geometry and earthquake loading is expected to be obtained from the limited test results. This project also plans to conduct numerical modelling to implement experimental approach. Two kinds of numerical approach will be adopted to model the dynamic response of a cohesive embankment. One is using finite difference software FLAC2D and the other is the Newmark‘s approach combined with a slope stability analysis method of slices, such as Bishop’s simplified method. These two numerical methods will be calibrated and verified with the results of dynamic centrifuge test and earthquake cases of India and Taiwan. After calibration, a great number of numerical tests will be performed to establish the relationships among permanent displacement, yield acceleration, consistency of clayey soil, slope geometry and earthquake loading. These relationships will be refined and simplified into simple design charts and tables so that the research results can be utilized in engineering practice. 研究期間：10001 ~ 10012
Relation:	財團法人國家實驗研究院科技政策研究與資訊中心
Appears in Collections:	[Department of Civil Engineering] Research Project

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