本文選題：土石壩　切入點：粘彈性人工邊界　出處：《大連理工大學》2014年碩士論文　論文類型：學位論文

【摘要】：目前土石壩抗震分析一般采用剛性邊界模型,假定邊界處各點的地震加速度相同,利用施加慣性力來實現(xiàn)地震動輸入,本文稱之為一致輸入方法。該方法采用的是一個能量封閉的系統(tǒng),在地震過程中,外行散射波無法透過邊界,使邊界上的反射波繼續(xù)影響壩體,未能考慮無限地基的輻射阻尼作用。此外,隨著壩體高度的增加,壩基的尺寸也隨之增大,地震波動使大壩底部各點的振動存在著較大的相位差,行波效應(yīng)的作用明顯增強。從以上方面可以看出,傳統(tǒng)的一致輸入方法很難真實地反映出大壩的地震響應(yīng)規(guī)律。 大多學者在研究土石壩抗震問題時假定地震波沿垂直方向入射,然而對于近場淺源地震或者場地條件比較復雜的壩址區(qū),地震波通常會以某個角度入射到地表,因此,采用合理的地震波動輸入方法,研究地震波從不同方向入射對土石壩地震反應(yīng)的影響是十分必要的。 本文為綜合考慮壩體和地基之間的相互作用、地基輻射阻尼和行波效應(yīng)對壩體動力反應(yīng)的影響,采用粘彈性人工邊界及其相應(yīng)的等效荷載地震動輸入方法,成功模擬了地震波不同方向入射的問題,討論了其對土石壩地震反應(yīng)的影響。主要完成了以下工作： 1.采用上述地震動輸入方法對一典型高土石壩模型進行地震反應(yīng)計算,討論了該方法在地基輻射阻尼及壩體與地基之間相互作用的模擬效果；從地震波頻譜特性、壩高、加速度峰值和地基剛度等四個方面,探討了該方法對高土石壩地震反應(yīng)的影響。 2.針對一典型高土石壩有限元模型,分別計算了SV波和P波以不同角度從不同方向入射時壩體的動力反應(yīng)。從壩頂加速度反應(yīng)、壩坡動力穩(wěn)定和壩體永久變形等方面,探討了地震波入射方向和行波效應(yīng)的影響。
[Abstract]:At present, the seismic analysis of the dam adopts the rigid boundary model, assuming the boundary points of the same seismic acceleration, using the inertial force applied to seismic input, this is called the uniform input method. This method is used in an energy closed system in the earthquake process, lay scattered wave cannot penetrate the boundary. The reflection on the boundary of the wave continues to influence the dam, failing to consider radiation damping effect of infinite foundation. In addition, with the increase of the height of the dam, the dam size increases, the seismic wave makes the vibration of each point in the bottom of the dam with larger phase difference, the effect of traveling wave effect is enhanced significantly. From the above aspects can be seen. Consistent with traditional input method is difficult to reflect the response of the dam earthquake.
Most scholars assume that the seismic wave incident along the vertical direction in the study of earth dam seismic, but for the near field of shallow earthquakes or site of complicated condition of dam area, the seismic wave is usually at an angle to the incident surface, therefore, the reasonable seismic wave input method, effects of seismic waves from different incident directions the seismic response is very necessary.
In this paper, considering the interaction between the dam and foundation, the influence of foundation radiation damping and traveling wave effect on the dynamic response of the dam, the viscoelastic artificial boundary and the equivalent load corresponding seismic input method successfully simulated earthquake wave with different incident directions, its influence on seismic response of earth rockfill dam is discussed mainly. The following work:
1. by using the method of earthquake input seismic response calculation of a typical high rockfill dam model, discusses the simulation result of the method is the interaction between the radiation damping of foundation and dam and foundation; from the spectral characteristics of seismic waves, dam height, peak acceleration and foundation stiffness in four aspects, discusses the influence of the reaction method the earthquake of high rockfill dam.
2. for a typical high rockfill dam finite element model, the dynamic response of SV wave and P wave at different angles from the different direction of incidence of the dam are calculated. The reaction from the horizontal acceleration, the dynamic stability of dam slope and dam permanent deformation etc., discusses the influence of incident angle of seismic wave and traveling wave effect.

【學位授予單位】：大連理工大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TV641;TV312

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本文編號：1625254