【摘要】：依據(jù)現(xiàn)行抗震設(shè)計(jì)規(guī)范建造的淺基礎(chǔ)橋,大多未進(jìn)行抗震驗(yàn)算,或至多是將這類橋梁看成是墩底固定在剛性地基上的懸臂結(jié)構(gòu),不考慮地震作用下的土-結(jié)構(gòu)相互作用問題,這些傳統(tǒng)的方法無法有效預(yù)測實(shí)際橋梁在地震作用下的動(dòng)力響應(yīng)。一些學(xué)者在研究中考慮了土-結(jié)構(gòu)相互作用效應(yīng),但研究不夠系統(tǒng)不夠深入,對于淺基橋土-結(jié)構(gòu)相互作用問題做進(jìn)一步系統(tǒng)的深入的研究是一個(gè)緊迫的課題。本文基于宏單元理論,建立了考慮土-結(jié)構(gòu)相互作用的淺基橋簡化模型,系統(tǒng)的研究了土-結(jié)構(gòu)相互作用對橋梁地震響應(yīng)的影響,選取工程實(shí)例,進(jìn)行了考慮土-結(jié)構(gòu)相互作用的橋梁地震響應(yīng)參數(shù)分析,主要完成了以下工作:(1)使用有限元軟件RUAUMOKO-3D分別建立了不考慮土-結(jié)構(gòu)相互作用的固定基礎(chǔ)模型、考慮線性土-結(jié)構(gòu)相互作用以及考慮非線性土-結(jié)構(gòu)相互作用的橋梁簡化模型,通過與其他建模方法以及文獻(xiàn)算例對比,驗(yàn)證了模型的正確性。(2)分別對比線性土-結(jié)構(gòu)相互作用模型和固定基礎(chǔ)模型、非線性土-結(jié)構(gòu)相互作用模型和固定基礎(chǔ)模型的地震響應(yīng),分析了土-結(jié)構(gòu)相互作用對橋梁地震響應(yīng)的影響。結(jié)果表明考慮線性土-結(jié)構(gòu)相互作用的淺基礎(chǔ)的系統(tǒng)搖擺響應(yīng)和考慮非線性土-結(jié)構(gòu)相互作用的淺基礎(chǔ)的搖擺分離響應(yīng)以及土的滯回特性極大的耗散了地震能量,考慮土-結(jié)構(gòu)相互作用的影響是為了更準(zhǔn)確的分析上部結(jié)構(gòu)的地震反應(yīng),但也應(yīng)同時(shí)注意到結(jié)構(gòu)位移響應(yīng)的增大以及殘余位移的產(chǎn)生衍生出其他的一些需要解決的課題。此外,通過對比線性土-結(jié)構(gòu)相互作用模型與非線性土-結(jié)構(gòu)相互作用模型地震響應(yīng)結(jié)果,分析不同的土-結(jié)構(gòu)相互作用類型對橋梁地震響應(yīng)分析結(jié)果帶來的影響。(3)基于宏單元法,分別建立考慮線性土-結(jié)構(gòu)相互作用以及非線性土-結(jié)構(gòu)相互作用的橋梁簡化模型,改變場地土的剪切波速、基礎(chǔ)寬度、土壤粘聚力等參數(shù),分別使用這兩類模型研究了不同結(jié)構(gòu)參數(shù)、土參數(shù)的改變對橋梁地震響應(yīng)的影響。分析表明,較大剪切波速和較大的基礎(chǔ)寬度有利于減小橋梁地震響應(yīng)。但增加基礎(chǔ)寬度對橋墩承載能力提出了更高要求,在橋梁抗震設(shè)計(jì)時(shí),要綜合考慮墩頂位移限值要求和墩底承載能力這兩方面因素。需要特別注意的是,當(dāng)考慮線性土-結(jié)構(gòu)相互作用時(shí),土壤粘聚力對橋梁結(jié)構(gòu)響應(yīng)無任何影響,但當(dāng)考慮非線性土-結(jié)構(gòu)相互作用時(shí),隨著土壤粘聚力的增大,結(jié)構(gòu)位移響應(yīng)減小,加速度響應(yīng)增大,當(dāng)土壤粘聚力小于一定值時(shí)結(jié)構(gòu)傾覆。
[Abstract]:Most of the shallow foundation bridges built according to the current seismic design code have not carried out seismic checking calculation, or at most regard such bridges as cantilever structures fixed on rigid foundation at the bottom of piers without considering the soil-structure interaction problem under earthquake action. These traditional methods can not effectively predict the dynamic response of actual bridges under earthquake action. Some scholars have considered the soil-structure interaction effect in the research, but the research is not systematic enough, so it is an urgent task to do further systematic research on soil-structure interaction of shallow foundation bridge. Based on macro element theory, a simplified model of shallow foundation bridge considering soil-structure interaction is established in this paper. The influence of soil-structure interaction on bridge seismic response is systematically studied. The seismic response parameter analysis of bridge considering soil-structure interaction is carried out. The main work is as follows: (1) the fixed foundation model without considering soil-structure interaction is established by using finite element software RUAUMOKO-3D. The simplified model of bridge considering linear soil-structure interaction and nonlinear soil-structure interaction is compared with other modeling methods and reference examples. The validity of the model is verified. (2) the seismic responses of linear soil-structure interaction model and fixed foundation model, nonlinear soil-structure interaction model and fixed foundation model are compared, respectively. The influence of soil-structure interaction on bridge seismic response is analyzed. The results show that the rocking response of shallow foundation considering linear soil-structure interaction and the rocking separation response of shallow foundation considering nonlinear soil-structure interaction and hysteretic characteristic of soil dissipate seismic energy greatly. The influence of soil-structure interaction is considered in order to analyze the seismic response of superstructure more accurately, but we should also pay attention to the increase of structural displacement response and the generation of residual displacement and derive some other problems that need to be solved. In addition, the seismic responses of the linear soil-structure interaction model and the nonlinear soil-structure interaction model are compared. The influence of different soil-structure interaction types on the seismic response of bridges is analyzed. (3) based on the macro element method, A simplified bridge model considering linear soil-structure interaction and nonlinear soil-structure interaction is established to change the shear wave velocity, foundation width and soil cohesion. The effects of different structural parameters and soil parameters on the seismic response of bridges are studied by using these two models. The analysis shows that the large shear wave velocity and the large foundation width are favorable to reduce the seismic response of the bridge. However, increasing the width of the foundation puts forward higher requirements for the bearing capacity of the bridge pier. In the seismic design of the bridge, two factors should be considered comprehensively: the limit value of the pier top displacement and the bearing capacity of the pier bottom. It is important to note that when linear soil-structure interaction is considered, soil cohesion has no effect on the bridge structure response, but when nonlinear soil-structure interaction is considered, the soil cohesion increases with the increase of soil cohesion. The displacement response of the structure decreases and the acceleration response increases. When the cohesive force of the soil is less than a certain value, the structure overturns.
【學(xué)位授予單位】：北京交通大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：U442.55

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本文編號(hào)：2302153