本文關(guān)鍵詞： 地震作用 加筋土擋墻 有限元分析 動(dòng)力性能　出處：《華南理工大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

【摘要】：從古代人們將草筋混入泥中修建加固墻壁到現(xiàn)代的加筋土路基，擋墻，橋臺(tái)等，加筋土技術(shù)已經(jīng)有一段悠久的應(yīng)用歷史了，其中加筋土擋墻由于有著造型美觀，建造經(jīng)濟(jì)，施工方便及技術(shù)性能優(yōu)良等優(yōu)點(diǎn)成為現(xiàn)代加筋土技術(shù)應(yīng)用的重要方面，備受工程界的青睞。與加筋土擋墻應(yīng)用歷史和范圍相比，對其理論研究顯得滯后與不足，尤其在動(dòng)力特性及動(dòng)力設(shè)計(jì)方面。我國是地震多發(fā)區(qū)，這要求土工結(jié)構(gòu)有一定的抗震性能，而我國以及其它各國對加筋土擋墻的抗震設(shè)計(jì)至今還沒有一套完善的理論與標(biāo)準(zhǔn)，所以對加筋土擋墻在地震作用下的動(dòng)力性能的研究就顯得十分的必要和迫切。本文主要針對加筋土擋墻地震作用下的動(dòng)力性能進(jìn)行仿真分析。主要研究內(nèi)容和取得的成果如下： （1）介紹了加筋土擋墻的發(fā)展歷史、國內(nèi)外研究動(dòng)態(tài)以及地震作用下加筋土擋墻的破壞實(shí)例。對加筋土擋墻的組成部分，選材要求及結(jié)構(gòu)特點(diǎn)等方面進(jìn)行了歸納與總結(jié)。介紹分析了土工格柵的加筋機(jī)理:摩擦加筋原理、準(zhǔn)粘聚力原理、均質(zhì)等代材料原理、等效圍壓理論及彈性層板理論。并對加筋土擋墻各種破壞模式及其內(nèi)外穩(wěn)定性設(shè)計(jì)方法進(jìn)行分析和總結(jié)。 （2）根據(jù)加筋土擋墻的結(jié)構(gòu)特點(diǎn)，將其簡化成平面應(yīng)變問題進(jìn)行分析。依據(jù)加筋土擋墻的組成材料特點(diǎn)，選擇適合的的單元類型。設(shè)置關(guān)鍵參數(shù)，利用ANSYS有限元軟件建立了由土體單元、筋材單元、接觸單元，面板單元組成的非線性有限元模型，設(shè)置關(guān)鍵參數(shù)，并進(jìn)行了地震力作用下有限元分析。 （3）從擋墻水平位移，加速度放大效應(yīng)，，筋帶拉力分布三個(gè)方面對加筋土擋墻模擬結(jié)果進(jìn)行分析。擋墻水平位移方面：在各級地震作用下，擋墻水平位移沿著墻高方向增大，在地震加速度較小時(shí)，擋墻沿著墻高方向的水平位移變化平緩，增量較小，在地震加速度較大時(shí)，擋墻沿著墻高方向水平位移的變化較大，增量較大。隨著地震波加速度峰值的增大，加筋土擋墻頂部一質(zhì)點(diǎn)的水平位移最大值呈增大的趨勢，遠(yuǎn)離擋板的點(diǎn)的水平位移越�。患咏钔翐鯄Φ淖畲笪灰泣c(diǎn)在頂部靠近面板處的地方；在地震加速度到達(dá)峰值的時(shí)刻，擋墻的水平位移并未達(dá)到最大。加速度放大效應(yīng)方面：擋墻質(zhì)點(diǎn)的加速度放大倍數(shù)隨地震加速度的峰值的增大而增大；沿墻高方向，加速度放大倍數(shù)呈變大的趨勢；加筋土擋墻頂部質(zhì)點(diǎn)的加速度放大倍數(shù)最大。筋帶拉力分布方面：在加速度峰值為0.1g的地震作用下，筋帶拉力最大值沿墻高方向增大，沿著筋帶長度方向減小，由于筋帶與擋板固定連接，筋帶拉力最大值在擋板與筋材連接處，在對擋墻的抗震設(shè)計(jì)時(shí)應(yīng)考慮對二者連接點(diǎn)的加固；在加速度峰值為0.2g～0.4g地震波作用下，筋帶拉力沿長度方向先增大后減小，隨著地震強(qiáng)度增大，潛在破裂面向后移動(dòng)，在擋墻筋材的長度設(shè)計(jì)時(shí)，應(yīng)考慮地震強(qiáng)度的影響。
[Abstract]:From ancient times people mixed grass bars into mud to build reinforced walls to modern reinforced earth subgrade, retaining wall, bridge abutment and so on, reinforced earth technology has a long history of application, in which reinforced earth retaining wall has beautiful shape, so it is economical to build. The advantages of convenient construction and excellent technical performance have become an important aspect of the application of modern reinforced earth technology, and have been favored by the engineering circles. Compared with the history and scope of application of reinforced earth retaining wall, the theoretical research on it is lagging behind and insufficient. Especially in the aspect of dynamic characteristics and dynamic design, our country is an earthquake prone area, which requires geotechnical structure to have certain seismic performance. However, there is no perfect theory and standard for seismic design of reinforced earth retaining wall in our country and other countries up to now. Therefore, it is very necessary and urgent to study the dynamic performance of reinforced earth retaining wall under earthquake. This paper mainly analyzes the dynamic performance of reinforced earth retaining wall under earthquake. The main research contents and results are as follows:. 1) the development history of reinforced earth retaining wall, the research trends at home and abroad, and the failure examples of reinforced earth retaining wall under earthquake action are introduced. The material selection requirements and structural characteristics are summarized and summarized. The reinforcement mechanism of geogrid is introduced and analyzed, including friction reinforcement principle, quasi-cohesive force principle, homogenization material principle, etc. The equivalent confining pressure theory and elastic laminate theory, and the analysis and summary of various failure modes and internal and external stability design methods of reinforced earth retaining wall are carried out. According to the structural characteristics of reinforced earth retaining wall, the problem of plane strain is simplified and analyzed. According to the material characteristics of reinforced earth retaining wall, the suitable element type is selected and the key parameters are set. A nonlinear finite element model consisting of soil element, steel element, contact element and panel element is established by using ANSYS software. The key parameters are set up and the finite element analysis is carried out under the action of seismic force. 3) the simulation results of reinforced earth retaining wall are analyzed from three aspects: horizontal displacement of retaining wall, acceleration amplification effect and distribution of tension force of reinforced soil. The horizontal displacement of retaining wall increases along the direction of wall height under earthquake action at all levels. When the earthquake acceleration is small, the horizontal displacement of the retaining wall along the direction of the wall height changes slowly, and the increment is small. When the earthquake acceleration is large, the horizontal displacement of the retaining wall along the direction of the wall height changes greatly. The increment is larger. With the increase of the peak acceleration of seismic wave, the maximum horizontal displacement of a particle at the top of reinforced earth retaining wall tends to increase, and the horizontal displacement of the point far away from the baffle is smaller. The maximum displacement of the reinforced earth retaining wall is near the top of the slab; at the moment when the seismic acceleration reaches its peak, The horizontal displacement of the retaining wall does not reach the maximum. In terms of acceleration amplification effect, the acceleration amplification multiple of the retaining wall particle increases with the increase of the peak value of the seismic acceleration, and along the direction of the wall height, the acceleration amplification multiple tends to increase. The maximum magnification of acceleration at the top of reinforced earth retaining wall is maximum. The maximum tensile force increases along the height of the wall and decreases along the direction of the length of the reinforcement band under the earthquake with a peak acceleration of 0.1 g. Because of the fixed connection between the steel strip and the retaining plate, the maximum tensile force of the steel band is at the joint of the retaining plate and the steel bar, and the reinforcement of the joint points should be considered in the seismic design of the retaining wall, under the action of the earthquake wave with a peak acceleration of 0.2 g / 0. 4 g, The tensile force of the reinforcement increases first and then decreases along the length direction. With the increase of the earthquake intensity, the potential rupture moves backward. The influence of seismic intensity should be taken into account in the length design of the retaining wall reinforcement.
【學(xué)位授予單位】：華南理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：U417.11

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