發(fā)布時間：2018-06-07 11:31

  本文選題：地震波反演 + 巖溶地基-筏板基礎(chǔ)-鋼框架結(jié)構(gòu)共同作用　； 參考：《廣西大學(xué)》2014年碩士論文

【摘要】：我國巖溶地區(qū)的面積約占我國國土總面積的三分之一,是世界上面積最大的巖溶地區(qū)之一；我國處在世界兩大地震帶之間,地震活動頻繁,地震造成的災(zāi)害也比較大,特別是近些年,每次地震災(zāi)害都會造成巨大的傷亡；目前,在巖溶地基上建造高層建筑主要的設(shè)計方法仍然采用常規(guī)設(shè)計方法或者經(jīng)驗法,容易造成人為的誤差,特別是對建筑抗震分析時,計算結(jié)果與實際的出入會更大,因此加強巖溶地基-基礎(chǔ)-上部結(jié)構(gòu)共同作用的研究是非常有必要的。本文采用數(shù)值模擬方法對巖溶地基-筏板基礎(chǔ)-鋼框架結(jié)構(gòu)共同作用進行了以下幾方面的研究：(1)采用EduShake軟件來對EI-Centro波進行反演,反演地質(zhì)條件采用巖溶區(qū)的一處場地,將EI-Centro波按照規(guī)范進行調(diào)幅后,從地表處反演至基巖處,經(jīng)過分析得出巖溶地質(zhì)對地震波具有放大作用和“濾波作用”。(2)建立巖溶地基-筏板基礎(chǔ)-鋼框架結(jié)構(gòu)的共同作用模型,通過與地基土體尺寸無限大時的模型作對比,確定了有限元-無限元耦合模型中有限元部分的土體尺寸：當(dāng)采用有限元-無限元耦合模型來考慮共同作用時,有限元部分尺寸不宜小于15倍的結(jié)構(gòu)橫向尺寸。(3)建立巖溶地基-筏板基礎(chǔ)-鋼框架結(jié)構(gòu)的共同作用模型,通過與地基土體尺寸無限大時的模型作對比,確定了有限元-無限元耦合模型中無限元部分的土體尺寸：即當(dāng)有限元的延伸長度取值大于有限元-無限元交界面距土體中心尺寸的1.5倍時,誤差已經(jīng)很小,本文有限元的延伸長度取有限元-無限元交界面距土體中心尺寸的2倍。(4)采用得到的耦合模型中土體有限元部分的尺寸和無限元部分的尺寸,建立巖溶地基-筏板基礎(chǔ)-鋼框架結(jié)構(gòu)的共同作用模型,分析考慮共同作用對上部結(jié)構(gòu)抗震性能的影響。結(jié)果表明考慮共同作用以后,上部結(jié)構(gòu)底部變形與內(nèi)力較不考慮共同作用相比增大較多,隨著層數(shù)的增加,增大的幅度逐漸減小,產(chǎn)生這種現(xiàn)象的原因是由于考慮共同作用以后,筏板基礎(chǔ)產(chǎn)生不均勻沉降,使得框架柱底部產(chǎn)生了較大的次生應(yīng)力,隨著層數(shù)的增加次生應(yīng)力逐漸減小。(5)建立巖溶地基-筏板基礎(chǔ)-鋼框架結(jié)構(gòu)的共同作用模型,分析土洞的存在對共同作用抗震性能的影響。結(jié)果表明地基土中由于土洞的存在,,使得地基土的剛度減小,在地震的作用下導(dǎo)致地基土的變形要比無土洞時大,進而上部結(jié)構(gòu)產(chǎn)生更大的內(nèi)力和變形。
[Abstract]:The area of karst area in China accounts for about 1/3 of the total land area of our country, and it is one of the largest karst areas in the world. In particular, in recent years, every earthquake disaster has caused huge casualties. At present, the main design methods for building high-rise buildings on karst foundations are still using conventional design methods or empirical methods, which can easily cause man-made errors. Especially for the seismic analysis of buildings, the difference between the calculated results and the actual results will be greater, so it is necessary to strengthen the study of the interaction between karst foundation and superstructure. In this paper, numerical simulation method is used to study the interaction of karst foundation, raft foundation and steel frame structure in the following aspects: the EduShake software is used to inverse the EI-Centro wave, and the geological conditions are retrieved from a site in the karst area. After amplitude modulation of EI-Centro wave in accordance with the specifications, inversion from the surface to the bedrock, it is concluded that karst geology can amplify the seismic wave and "filter" the seismic wave. 2) to establish the mutual action model of karst foundation, raft foundation and steel frame structure. By comparing with the finite element model when the soil size is infinite, the soil size of the finite element part of the finite element coupling model is determined. When the finite element infinite element coupling model is used to consider the joint action, The finite element method should not be less than 15 times the transverse size of the structure.) the model of the interaction between karst foundation, raft foundation and steel frame structure is established, and the model is compared with the model when the soil size is infinite. The soil size of the infinite element in the finite element coupling model is determined. That is, when the extension length of the finite element is 1.5 times larger than that of the interface between the finite element and the infinite element, the error is very small. In this paper, the extension length of the finite element is taken as 2 times that of the interface between the finite element and the infinite element from the center of the soil, and the size of the finite element part of the soil and the size of the infinite element part in the coupling model are obtained. The interaction model of karst foundation raft foundation and steel frame structure is established and the effect of joint action on seismic behavior of superstructure is analyzed. The results show that the deformation at the bottom of the superstructure increases more than that of the internal force without considering the interaction, and with the increase of the number of layers, the amplitude of the increase decreases gradually. The reason for this phenomenon is that considering the joint action, the raft foundation produces uneven settlement, which results in a large secondary stress at the bottom of the frame column. With the increase of the number of layers, the secondary stress decreases gradually.) the interaction model of karst foundation, raft foundation and steel frame structure is established, and the influence of the existence of soil hole on the seismic behavior of the joint action is analyzed. The results show that the stiffness of the foundation soil decreases due to the existence of the soil hole, and the deformation of the foundation soil is larger than that of the non-soil hole under the action of earthquake, and the superstructure produces greater internal force and deformation.
【學(xué)位授予單位】：廣西大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TU311.3;TU435
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本文編號：1991021