地震作用下土—結構相互作用對淺基礎橋結構響應的影響
發(fā)布時間：2018-10-31 12:17
【摘要】：依據現行抗震設計規(guī)范建造的淺基礎橋,大多未進行抗震驗算,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構,不考慮地震作用下的土-結構相互作用問題,這些傳統(tǒng)的方法無法有效預測實際橋梁在地震作用下的動力響應。一些學者在研究中考慮了土-結構相互作用效應,但研究不夠系統(tǒng)不夠深入,對于淺基橋土-結構相互作用問題做進一步系統(tǒng)的深入的研究是一個緊迫的課題。本文基于宏單元理論,建立了考慮土-結構相互作用的淺基橋簡化模型,系統(tǒng)的研究了土-結構相互作用對橋梁地震響應的影響,選取工程實例,進行了考慮土-結構相互作用的橋梁地震響應參數分析,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-結構相互作用的固定基礎模型、考慮線性土-結構相互作用以及考慮非線性土-結構相互作用的橋梁簡化模型,通過與其他建模方法以及文獻算例對比,驗證了模型的正確性。(2)分別對比線性土-結構相互作用模型和固定基礎模型、非線性土-結構相互作用模型和固定基礎模型的地震響應,分析了土-結構相互作用對橋梁地震響應的影響。結果表明考慮線性土-結構相互作用的淺基礎的系統(tǒng)搖擺響應和考慮非線性土-結構相互作用的淺基礎的搖擺分離響應以及土的滯回特性極大的耗散了地震能量,考慮土-結構相互作用的影響是為了更準確的分析上部結構的地震反應,但也應同時注意到結構位移響應的增大以及殘余位移的產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-結構相互作用模型與非線性土-結構相互作用模型地震響應結果,分析不同的土-結構相互作用類型對橋梁地震響應分析結果帶來的影響。(3)基于宏單元法,分別建立考慮線性土-結構相互作用以及非線性土-結構相互作用的橋梁簡化模型,改變場地土的剪切波速、基礎寬度、土壤粘聚力等參數,分別使用這兩類模型研究了不同結構參數、土參數的改變對橋梁地震響應的影響。分析表明,較大剪切波速和較大的基礎寬度有利于減小橋梁地震響應。但增加基礎寬度對橋墩承載能力提出了更高要求,在橋梁抗震設計時,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,當考慮線性土-結構相互作用時,土壤粘聚力對橋梁結構響應無任何影響,但當考慮非線性土-結構相互作用時,隨著土壤粘聚力的增大,結構位移響應減小,加速度響應增大,當土壤粘聚力小于一定值時結構傾覆。
[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.
【學位授予單位】：北京交通大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：U442.55
本文編號：2302153
[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.
【學位授予單位】：北京交通大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：U442.55
【參考文獻】
相關期刊論文 前2條
1 朱秀云;潘蓉;李建波;;考慮SSI效應的核電站廠房樓層反應譜對比分析[J];核技術;2013年04期
2 陳興沖,朱f^;允許提離的彈塑性Winkler地基上橋墩的地震反應[J];工程力學;1999年05期
，本文編號：2302153
本文鏈接：http://sikaile.net/kejilunwen/daoluqiaoliang/2302153.html
