本文選題：樁基　切入點：樁-土相互作用　出處：《哈爾濱工業(yè)大學(xué)》2016年博士論文

【摘要】：地震中液化引發(fā)場地側(cè)向擴展是導(dǎo)致樁基震害的主要原因之一。振動臺試驗是研究液化側(cè)向擴展場地樁-土動力相互作用最有效的途徑之一。數(shù)值計算是振動臺試驗的有力補充,同時也是將理論研究工作拓展到實際工程的必要技術(shù)環(huán)節(jié)。然而,目前研究工作更多集中于室內(nèi)試驗的數(shù)值計算和擬靜力計算,應(yīng)用于實際工程尚缺乏充分的試驗與理論依據(jù)。鑒于此,本文針對地震下液化側(cè)向擴展場地樁-土相互作用體系,通過大型樁基振動臺試驗和理論分析相結(jié)合的方法,建立液化側(cè)向擴展場地樁-土動力相互作用簡化分析方法并提出樁-土界面連接方式。同時,將該連接應(yīng)用于液化側(cè)向擴展場地樁基振動臺試驗數(shù)值分析,研究數(shù)值模型的主要影響因素。此外,考慮樁基非線性和側(cè)向擴展大變形會導(dǎo)致計算量增大,為提高計算效率,建立群樁振動臺試驗并行數(shù)值模型,并驗證其可靠性。最后,將該方法應(yīng)用于實際液化側(cè)向擴展場地預(yù)應(yīng)力混凝土群樁的數(shù)值模擬。具體研究內(nèi)容、方法及成果如下:1.大型液化側(cè)向擴展場地樁基(單樁和群樁)振動臺試驗。針對典型近岸液化側(cè)向擴展場地特點,借鑒同類振動臺試驗設(shè)計經(jīng)驗,通過設(shè)置岸壁觸發(fā)砂土液化側(cè)向擴展,成功實現(xiàn)了動力輸入下砂土液化側(cè)向擴展,并對液化側(cè)向擴展場地土層孔壓、加速度和側(cè)向擴展位移及樁的側(cè)向位移和彎矩響應(yīng)進(jìn)行系統(tǒng)分析。2.液化側(cè)向擴展場地單樁簡化分析方法。針對單樁基振動臺試驗,基于非線性Winkler地基梁模型,采用彈性梁單元模擬樁,修正的p-y彈簧單元模擬液化土體,零長度單元模擬樁底連接,將試驗記錄的側(cè)向擴展位移作為p-y彈簧單元外側(cè)節(jié)點的位移剖面,建立了液化側(cè)向擴展場地樁-土相互作用簡化分析方法,基于試驗結(jié)果對簡化分析方法的可靠性進(jìn)行驗證;并分析了樁模量、樁徑和樁底剛度對樁基響應(yīng)的影響。3.樁-土界面連接方式。在剛性樁-土界面連接的基礎(chǔ)上,通過定義界面的剪切屈服力和增加并聯(lián)的兩類零長度單元,模擬地震過程中樁-土界面剪切力的耦合效應(yīng),實現(xiàn)樁-土界面的滑移,避免土體液化側(cè)向擴展過程中樁上產(chǎn)生過大的軸向力。4.液化側(cè)向擴展場地單樁基振動臺試驗數(shù)值模擬。針對單樁基振動臺試驗,利用初始狀態(tài)分析法,通過施加節(jié)點孔壓和相應(yīng)節(jié)點荷載模擬自由水體,采用并列線性梁單元模擬岸壁,基于上述的樁-土界面連接方法,建立了液化側(cè)向擴展場地單樁基振動臺數(shù)值模型,并基于振動臺試驗結(jié)果對數(shù)值模型的可靠性進(jìn)行驗證;在此基礎(chǔ)上,分析了阻尼系數(shù)、滲透系數(shù)和上部結(jié)構(gòu)配重對樁-土動力相互作用的影響。5.液化側(cè)向擴展場地群樁基振動臺試驗數(shù)值模擬。在單樁基振動臺數(shù)值模型的基礎(chǔ)上,將單樁體系轉(zhuǎn)變?yōu)槿簶扼w系,建立相應(yīng)的群樁振動臺數(shù)值模型,并驗證其有效性�；诖�,考慮混凝土樁基的非線性,建立了群樁基振動臺試驗的并行計算數(shù)值模型,并基于串行數(shù)值計算結(jié)果驗證并行計算方法的可靠性,重點分析了群樁的彎矩-曲率和纖維應(yīng)變響應(yīng)特性。6.實際液化側(cè)向擴展場地預(yù)應(yīng)力混凝土群樁基數(shù)值模擬�？紤]混凝土樁預(yù)應(yīng)力的特點,數(shù)值模擬中,將預(yù)應(yīng)力混凝土樁和土體單獨建模,確保預(yù)應(yīng)力作用下混凝土樁自由變形,同時在重力作用下土體位移置零。在此基礎(chǔ)上,采用上述樁-土界面連接單元組裝樁和土體模型,建立實際液化擴側(cè)流場地預(yù)應(yīng)力混凝土群樁基并行計算數(shù)值模型,并分析地震下樁基的軸力、剪力、彎矩、曲率和纖維應(yīng)變響應(yīng)特性。本文研究成果進(jìn)一步加深對液化側(cè)向擴展場地樁基地震響應(yīng)特性和震害問題的理解。尤其是所完成的液化側(cè)向擴展場地樁基大型振動臺試驗、針對試驗所做的大量的數(shù)值模擬分析和實際液化側(cè)向擴展場地群樁基并行計算數(shù)值模擬分析,以及分析所獲得的一些認(rèn)識。這將為同類試驗和數(shù)值模擬研究提供必要技術(shù)細(xì)節(jié),對于進(jìn)一步深入研究液化側(cè)向擴展場地樁基地震響應(yīng)特性具有重要意義,并為逐步完善液化側(cè)向擴展場地樁基抗震設(shè)計積累寶貴的基礎(chǔ)資料。
[Abstract]:The earthquake caused liquefaction ground lateral expansion is one of the main causes of pile damage. Shaking table test study on liquefaction lateral spreading ground soil pile dynamic interaction is one of the most effective way. Numerical calculation is a strong complement of shaking table test, but also the theoretical research work to expand the essential technology to practical engineering. However, numerical research now is more focused on laboratory tests and pseudo static, applied to practical engineering test and lack of sufficient theoretical basis. In view of this, based on the lateral seismic liquefaction to expand the field of pile-soil interaction system, combining the large shaking table experiments and theoretical analysis of pile foundation, establish liquefaction the lateral extension of site soil pile dynamic interaction analysis method is proposed to simplify the pile-soil interface connection. At the same time, the connection is applied to lateral expansion liquefaction Analysis of pile vibration table test to show the numerical research the main influencing factors of numerical model. In addition, expansion of large deformation will lead to increase the amount of calculation of pile foundation considering the nonlinearity and the lateral, in order to improve the calculation efficiency, the establishment of group pile shaking table test of parallel numerical model, and verify its reliability. Finally, the method is applied to the actual liquefaction the lateral extension of numerical simulation of concrete pile site prestressed concrete research content, methods and results are as follows: 1. large liquefaction lateral spreading site pile (single pile and pile group). The shaking table test for typical offshore liquefaction lateral expansion characteristics of the site, from the same vibration test design experience, by setting the wall of sand liquefaction lateral spreading the successful implementation of the power input, lateral sand liquefaction and lateral spreading of liquefaction expansion, soil pore water pressure, lateral displacement and lateral displacement and acceleration expansion pile And the moment response system analysis of.2. liquefaction lateral spreading ground pile. The simplified analysis method for single pile vibration table test, nonlinear Winkler model based on the elastic foundation beam, beam element to simulate pile, p-y spring element simulation of the liquefied soil amendment, zero length element simulation of pile bottom connection, the lateral displacement as expansion of the test record the displacement profile p-y lateral spring element node, establish the liquefaction lateral spreading field of pile-soil interaction simplified analysis method based on the test results, verify the reliability of the simplified analysis method; and the analysis of the pile modulus, pile diameter and pile stiffness of pile foundation response.3. pile-soil interface based on connection. Rigid pile soil interface connection, two types of zero length element through the shear interface definition of yield force and increase the parallel coupling, pile-soil interface shear stress in the process of earthquake simulation The slip effect, pile-soil interface, avoid soil liquefaction lateral spreading process of pile on excessive axial force.4. liquefaction lateral spreading numerical simulation of single pile ground shaking table test for single pile vibration table test, using the method of initial state, by applying nodal pore pressure and the corresponding node load simulation of free water. Using the parallel linear beam element to simulate the wall connection method of pile-soil interface based on established liquefaction lateral spreading numerical field single pile vibration table model, and based on the results of shaking table test to verify the reliability of the numerical model; on this basis, analysis of the damping coefficient, permeability coefficient and mass of superstructure on the pile soil dynamic interaction.5. liquefaction lateral spreading simulation site pile foundation vibration test. Numerical basis of numerical model in single pile vibration table, the single pile system into Pile group system, the establishment of numerical pile shaking table model accordingly, and verifies its validity. Based on this, considering the nonlinear concrete pile foundation, pile foundation established parallel vibration test and numerical calculation model, calculation results verify the reliability of parallel computing method based on serial numerical analyses of Moment Curvature of pile group and the fiber strain response of the.6. actual liquefaction lateral spreading numerical simulation of prestressed concrete pile foundation site. Considering the characteristics of prestressed concrete pile, numerical simulation, the prestressed concrete pile and soil are modeled separately, ensure the prestressed concrete pile under free deformation, while in soil under the action of gravity position zero displacement. On this basis, using the above pile soil interface connecting unit assembled pile and soil model, establish the actual liquefaction expansion numerical model of flow field of parallel side prestressed concrete pile foundation, and Analysis of the axial force of the pile foundation under seismic shear force, bending moment, curvature and fiber strain response characteristics. The results of this study further expansion characteristics and understand the problem of earthquake response of pile foundation on seismic liquefaction lateral site. Especially the liquefaction induced lateral vibration of large pile extension site test, a large number of tests made for numerical simulation analysis and actual liquefaction lateral spreading parallel computing numerical simulation analysis of soil pile foundation, and some understanding of the analysis. This will provide the necessary technical details for the test and numerical simulation study of similar, for further study on liquefaction lateral spreading plays an important role in the response characteristics of pile foundation seismic site, and gradually improve the liquefaction lateral spreading ground pile seismic design of accumulated precious data.

【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2016
【分類號】：TU473.1;TU435

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1 蘇雷;液化側(cè)向擴展場地樁—土體系地震模擬反應(yīng)分析[D];哈爾濱工業(yè)大學(xué);2016年

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本文編號：1656845