本文關(guān)鍵詞：液化場地橋梁群樁基地震反應(yīng)影響因素分析　出處：《哈爾濱工業(yè)大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 橋梁群樁基 地震反應(yīng) 三維有限元模擬 振動臺試驗(yàn) 液化場地

【摘要】：場地液化是導(dǎo)致樁基橋梁震害的重要原因之一。液化場地樁-土動力相互作用研究是解決液化場地樁基橋梁抗震問題的有效途徑。液化場地橋梁樁基震害,地震中孔隙水難以排出是可液化土動力性能改變的主要原因,土中孔隙水壓力上升引起有效應(yīng)力降低而導(dǎo)致土的強(qiáng)度損失或完全喪失強(qiáng)度,進(jìn)而嚴(yán)重影響橋梁樁基穩(wěn)定性、或使之抗震性能完全喪失而致使橋梁倒塌。鑒于上述,本文針對液化場地樁-土地震相互作用問題,采用振動臺試驗(yàn)且理論分析相結(jié)合手段,開展液化場地橋梁群樁基地震反應(yīng)與影響因素研究工作。本文主要研究工作與取得的若干認(rèn)識如下:(1)采用鋼筋混凝土群樁-柱墩基礎(chǔ)型式,針對表層覆蓋粘土層的液化場地,實(shí)施可液化場地橋梁樁基地震反應(yīng)振動臺試驗(yàn),研究了場地液化過程中橋梁樁基地震反應(yīng)規(guī)律與場地動力特性。并基于OpenSees有限元數(shù)值模擬平臺,直接針對上述振動臺試驗(yàn),樁采用基于歐拉-伯努利梁理論建立的梁-柱單元模擬,樁-土動力相互作用采用考慮體積效應(yīng)的剛性連接單元處理,建立試驗(yàn)受控條件下液化場地樁-土動力相互作用三維有限元分析模型與相應(yīng)的計(jì)算方法。通過樁基近場土體加速度、孔壓、樁身應(yīng)力等數(shù)值模擬與振動臺試驗(yàn)結(jié)果比較分析,驗(yàn)證了建立的有限元分析模型與相應(yīng)的計(jì)算方法的正確性。(2)采用所建立的三維有限元分析模型與相應(yīng)的計(jì)算方法,基于振動臺試驗(yàn)結(jié)果,針對液化場地樁-土-橋梁結(jié)構(gòu)動力相互作用,樁基為2×2群樁輸入El Centro波進(jìn)行反復(fù)的數(shù)值模擬,以墩重、墩高、樁間距、上部土層滲透系數(shù)等為基本控制量,建立不同參數(shù)下近場土體加速度、土體有效應(yīng)力下降速率、樁身彎矩及剪力、樁位移及加速度等時程曲線,從而分析上述主要因素對化場地樁-土動力相互作用的影響情況。(3)以上述2×2群樁數(shù)值模型為基礎(chǔ),擴(kuò)展出2PS群樁模型(2根樁在一行)、2PP群樁模型(2根樁在一列)、3PS群樁模型、3PP群樁模型、3×3群樁模型。根據(jù)上述數(shù)值模型所用變量,針對不同配置群樁基礎(chǔ)對液化場地樁-土地震相互作用的影響展開具體分析。
[Abstract]:Site liquefaction is one of the important causes of earthquake damage of pile foundation bridge. The study of pile-soil dynamic interaction in liquefaction site is an effective way to solve the seismic problem of pile foundation bridge in liquefaction site. The main reason for the dynamic change of liquefiable soil is that the pore water is difficult to be discharged in earthquake. The increase of pore water pressure in the soil leads to the decrease of effective stress which leads to the strength loss or complete loss of soil strength. Furthermore, the stability of bridge pile foundation is seriously affected, or the seismic behavior of bridge is completely lost and the bridge collapses. In view of the above mentioned, the pile-soil interaction in liquefaction site is discussed in this paper. The shaking table test and theoretical analysis were used. The research work on seismic response and influencing factors of bridge group pile foundation in liquefaction site is carried out in this paper. The main research work and some understandings obtained in this paper are as follows: 1) the reinforced concrete pile-column pier foundation type is adopted. For the liquefaction site covered with clay layer, the shaking table test of seismic response of bridge pile foundation in liquefiable site is carried out. The seismic response law and site dynamic characteristics of bridge pile foundation during site liquefaction are studied. Based on the OpenSees finite element numerical simulation platform, the shaking table test is carried out directly. The pile is simulated by the beam-column element based on the Euler-Bernoulli beam theory, and the pile-soil dynamic interaction is treated by the rigid connection element considering the volume effect. A three-dimensional finite element analysis model and corresponding calculation method for pile-soil dynamic interaction in liquefaction site under controlled experimental conditions were established. The results of numerical simulation and shaking table test are compared and analyzed. The correctness of the established finite element analysis model and the corresponding calculation method is verified. The established three-dimensional finite element analysis model and the corresponding calculation method are adopted, based on the shaking table test results. In view of the pile-soil-bridge structure dynamic interaction in liquefaction site, the pile foundation is inputted to El Centro wave for 2 脳 2 pile groups, and the pile weight, pier height and pile spacing are simulated repeatedly. The soil permeability coefficient of the upper layer is the basic control quantity. The time history curves such as near-field soil acceleration, soil effective stress decreasing rate, pile bending moment and shear force, pile displacement and acceleration are established under different parameters. The influence of the above main factors on the pile-soil dynamic interaction is analyzed. (3) based on the above 2 脳 2 pile group numerical model, the 2PS pile group model with two piles in one row is extended. 2PP pile group model and two piles in a row of pile group model 3PP group model and 3 脳 3 pile group model. According to the variables used in the above numerical model. The effects of different pile groups on the pile-soil seismic interaction in liquefaction sites are analyzed in detail.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：U443.1;U442.55

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相關(guān)期刊論文 前1條

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本文編號：1419238