本文選題：CFG樁 + 復(fù)合地基�。� 參考：《中國(guó)地質(zhì)大學(xué)(北京)》2015年碩士論文

【摘要】：作為現(xiàn)代高層建筑軟土地基處理的主要手段,CFG樁復(fù)合地基以其優(yōu)越的地基加固性能在我國(guó)得到了廣泛的應(yīng)用。同時(shí),我國(guó)作為地震高發(fā)的國(guó)家,城市的高速發(fā)展深受地震自然災(zāi)害的制約。因此,對(duì)CFG樁復(fù)合地基抗震性能的深入研究具有深遠(yuǎn)的意義。本文通過(guò)對(duì)CFG樁復(fù)合地基的承載機(jī)理及破壞機(jī)理的分析,利用LS-DYNA有限元?jiǎng)恿W(xué)分析軟件,對(duì)CFG樁復(fù)合地基抗震性能的動(dòng)力學(xué)特性進(jìn)行了數(shù)值分析研究,同時(shí),進(jìn)一步研究了CFG樁復(fù)合地基設(shè)計(jì)參數(shù)對(duì)CFG樁復(fù)合地基抗震性能的影響。本文通過(guò)對(duì)CFG樁復(fù)合地基抗震性能的分析研究,獲得主要成果如下:1)在地震荷載作用下,CFG樁復(fù)合地基破壞的判別主要是通過(guò)CFG樁復(fù)合地基樁體的位移、應(yīng)力進(jìn)行判斷。當(dāng)樁體截面拉應(yīng)力在樁體截面抗拉強(qiáng)度范圍內(nèi),樁頂水平位移在水平位移容許值范圍內(nèi)時(shí),樁體不會(huì)產(chǎn)生破壞,復(fù)合地基處于安全狀態(tài)。2)本文建立了地震荷載作用下CFG樁復(fù)合地基動(dòng)力學(xué)數(shù)值模型。對(duì)地震作用下CFG樁復(fù)合地基不同位置樁體及樁間土的水平及豎向加速度、位移、應(yīng)力進(jìn)行了對(duì)比分析,得到了樁體水平及豎向加速度、位移的變化規(guī)律,同時(shí),得到了樁體及樁間土水平及豎向應(yīng)力變化規(guī)律:(1)在地震荷載作用下,CFG樁復(fù)合地基樁體的水平加速度由樁頂至底部隨深度的增加先減小后增大;(2)水平位移呈現(xiàn)隨深度的增加不斷減小的規(guī)律;(3)水平應(yīng)力隨深度的增加先增大后減小,同時(shí),邊樁較中心樁的水平應(yīng)力更大;(4)邊樁產(chǎn)生的豎向加速度比中心樁豎向加速度大;(5)邊樁豎向位移遠(yuǎn)大于中心樁的豎向位移;(6)樁體豎向應(yīng)力隨深度的增加先增大后減小。3)將不同的設(shè)計(jì)參數(shù)(樁徑、樁長(zhǎng)、樁間距)作為變量參數(shù),通過(guò)對(duì)比分析,得到了各設(shè)計(jì)參數(shù)對(duì)CFG樁復(fù)合地基抗震性能的影響:(1)增大樁體直徑可以減小產(chǎn)生的加速度、變形及樁體的水平應(yīng)力,提高復(fù)合地基的抗震性能。但是,這會(huì)增大樁體的豎向應(yīng)力易導(dǎo)致樁體的破壞;(2)增加樁體長(zhǎng)度可以減小復(fù)合地基受地震波作用所產(chǎn)生的加速度、變形及樁體豎向應(yīng)力,提高復(fù)合地基的抗震性能。但是,這會(huì)增大樁體的水平應(yīng)力導(dǎo)致樁體的破壞;(3)增大樁間距對(duì)樁體及樁間土地震作用下所產(chǎn)生的加速度及位移影響很小,同時(shí)其應(yīng)力呈減小的趨勢(shì)。
[Abstract]:CFG pile composite foundation, as the main means of soft soil foundation treatment in modern high-rise buildings, has been widely used in China because of its excellent foundation strengthening performance. At the same time, as a country with high incidence of earthquakes, the rapid development of cities is restricted by earthquake natural disasters. Therefore, it is of great significance to study the seismic behavior of CFG pile composite foundation. Based on the analysis of bearing mechanism and failure mechanism of CFG pile composite foundation, the dynamic characteristics of seismic behavior of CFG pile composite foundation are studied numerically by using LS-DYNA finite element dynamic analysis software. The influence of the design parameters of CFG pile composite foundation on the seismic behavior of CFG pile composite foundation is further studied. Based on the analysis of the seismic behavior of the CFG pile composite foundation, the main results are as follows: 1) the main result of judging the damage of the CFG pile composite foundation under the earthquake load is mainly through the displacement and stress of the pile body of the CFG pile composite foundation. When the tensile stress of the pile section is in the range of tensile strength of the pile section and the horizontal displacement of the top of the pile is within the allowable range of the horizontal displacement, the pile body will not be destroyed. In this paper, the dynamic numerical model of CFG pile composite foundation under earthquake load is established. The horizontal and vertical acceleration, displacement and stress of pile and soil in different positions of CFG pile composite foundation under seismic action are compared and analyzed, and the variation law of horizontal and vertical acceleration and displacement of pile body are obtained, at the same time, The rule of horizontal and vertical stress variation of pile and soil between piles is obtained. (1) the horizontal acceleration of CFG pile composite foundation under earthquake load decreases first with the increase of pile depth and then increases with depth.) the horizontal displacement of CFG pile composite foundation decreases with depth and then increases with depth. The horizontal stress increases first and then decreases with the increase of depth. At the same time, Vertical displacement of side pile is much greater than that of central pile.) Vertical stress of side pile increases first and then decreases with the increase of depth. (5) Vertical displacement of side pile is much greater than that of center pile (4) the vertical acceleration of edge pile is greater than that of center pile (5) the vertical displacement of side pile is much greater than that of center pile (4) the vertical stress of side pile increases first and then decreases with the increase of depth. Small. 3) will be different design parameters (pile diameter, By comparing and analyzing the influence of design parameters on seismic behavior of CFG pile composite foundation, the influence of different design parameters on seismic behavior of CFG pile composite foundation is obtained. The increase of pile diameter can reduce the acceleration, deformation and horizontal stress of pile body. Improve the seismic performance of composite foundation. However, this will increase the vertical stress of the pile and lead to the failure of the pile. Increasing the length of the pile can reduce the acceleration, deformation and vertical stress of the composite foundation caused by seismic waves, and improve the seismic performance of the composite foundation. However, this will increase the horizontal stress of the pile and lead to the failure of the pile. (3) increasing the spacing of the pile has little effect on the acceleration and displacement of the pile and the soil between the piles, and its stress tends to decrease.
【學(xué)位授予單位】：中國(guó)地質(zhì)大學(xué)(北京)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TU470;TU435

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 鄭東明,鄧安福,呂鎮(zhèn)江;CFG樁復(fù)合地墓褥墊層效用的有限元分析[J];地下空間;1999年02期

2 徐燁,陳國(guó)興,莊海洋;水泥土樁復(fù)合地基場(chǎng)地地震效應(yīng)分析[J];防災(zāi)減災(zāi)工程學(xué)報(bào);2005年02期

3 張晶,李斌;CFG樁復(fù)合地基承載力的試驗(yàn)研究[J];合肥工業(yè)大學(xué)學(xué)報(bào)(自然科學(xué)版);1999年05期

4 吳春林;閻明禮;楊軍;唐建中;;水泥粉煤灰碎石樁的特性及其應(yīng)用[J];建筑技術(shù);1992年01期

5 王偉,楊堯志;水泥粉煤灰碎石樁復(fù)合地基抗震性能分析[J];世界地震工程;2000年02期

6 李寧,韓煊;褥墊層對(duì)復(fù)合地基承載機(jī)理的影響[J];土木工程學(xué)報(bào);2001年02期

7 牛春良,楊春田;樁基的減震性能分析[J];特種結(jié)構(gòu);2000年03期

8 毛前,龔曉南;樁體復(fù)合地基柔性墊層的效用研究[J];巖土力學(xué);1998年02期

9 徐自國(guó),宋二祥;剛性樁復(fù)合地基抗震性能的有限元分析[J];巖土力學(xué);2004年02期

10 鮑鵬;姜忻良;盛桂琳;;勁性攪拌樁復(fù)合地基承載性能靜動(dòng)力分析[J];巖土力學(xué);2007年01期

，

本文編號(hào)：1812317