上承式肋拱渡槽抗震性能研究

发布时间：2018-10-04 23:24

【摘要】：渡槽是远距离调水工程和灌区水工建筑物中应用最广泛的交叉建筑物之一，我国是一个多地震国家。地震区渡槽区别于一般建筑物，除承受水压、自重等静力荷载外，还承受风、地震等动力荷载，因而对渡槽结构的抗震分析难度较大。我国目前尚无关于渡槽结构的抗震设计规范，对渡槽的抗震研究主要集中在槽身结构选型、动力荷载下水体晃动等方面，对渡槽支承结构的研究较少，运用时程分析法对渡槽支撑结构的抗震研究则更少。本文借鉴国内外关于桥梁、渡槽结构、地震动力时程分析法以及地震波的研究成果，以东滑峪渡漕为例，运用ANSYS进行动力时程分析。在过水流量、跨度、抗震设防烈度及地基承载一定的情况下，运用不同实验设计方案（单因素、正交试验），分别改变矢跨比、拱轴线形式、排列方式、排架密度进行动力时程分析，最终得到既满足安全性又具有显著经济效益和工程价值的结构参数，主要工作内容如下：（1）研究国内外关于桥梁、渡槽结构模型的简化方法，确定渡槽槽身结构、支撑结构以及槽内水体简化模型的单元类型，边界约束条件，支撑排架与槽身的节点耦合等。在空槽工况和过水工况下，对东滑峪渡漕进行静力分析、模态分析，在此基础上施加横槽向地震激励、顺槽向地震激励，运用时程分析法进行动力时程分析。通过静力分析，研究内力（轴力、剪力、面内弯矩、面外弯矩）沿主拱圈的分布规律。通过动力时程分析，研究主拱圈位移、内力分布情况，分别确定其位移最大值、内力最大值截面位置。将静力分析结果与动力分析结果组合，确定主拱圈最不利位置。（2）运用单因素法安排实验，改变结构的矢跨比、拱轴线形式、排列方式以及排架密度，建立有限元模型，并进行动力分析，将动力分析结果与静力分析结果组合，通过对比拱脚内力极值（轴力、剪力、面内弯矩、面外弯矩）和应力极值，分别确定最优矢跨比、拱轴线形式、排列方式、排架密度。（3）运用正交试验法安排实验，建立有限元模型，并进行动力分析，将动力分析结果与静力分析结果组合，运用SPSS软件分别对拱脚内力极值和应力极值进行方差分析，，确定因素主次顺序，综合考虑，最终确定最优组合因素水平，即最优结构参数组合。单因素法得：最优矢跨比为1/6，最优拱轴线形式为悬链线，最优排列方式为拱顶不设排架，最优排架密度为原排架密度。正交试验法得：除横槽向地震激励下，最优排架排列方式为拱顶设置排架，其他最优结构参数与单因素法相同。
[Abstract]:Aqueduct is one of the most widely used cross structures in remote water transfer project and irrigation area. China is a country with many earthquakes. The aqueduct in earthquake area is different from the general building. Besides static load such as water pressure and deadweight, it also bears dynamic loads such as wind and earthquake, so the seismic analysis of aqueduct structure is difficult. At present, there is no seismic design code for aqueduct structure in China. The seismic research of aqueduct is mainly focused on the selection of aqueduct structure, the sloshing of water body under dynamic load and so on, but the research on aqueduct supporting structure is less. The seismic analysis of aqueduct braces by time history analysis is less. This paper draws lessons from the research results of bridge, aqueduct structure, seismic dynamic time-history analysis and seismic wave at home and abroad, and uses ANSYS as an example to carry out dynamic time-history analysis. Under the conditions of water flow, span, seismic fortification intensity and foundation bearing capacity, different experimental design schemes (single factor, orthogonal test) are used to change the rise-span ratio, the form of arch axis, and the arrangement mode, respectively. Dynamic time history analysis of the bent density is carried out, and the structural parameters which satisfy the safety and have significant economic benefit and engineering value are obtained. The main work is as follows: (1) the bridge at home and abroad is studied. The simplified method of aqueduct structure model, the element type of aqueduct body structure, bracing structure and water body simplification model, boundary constraint condition, coupling between bracing frame and trough body, etc. On the basis of static analysis and modal analysis, the dynamic time-history analysis is carried out on the condition of empty trough and over-water. On the basis of this, the transverse seismic excitation and the seismic excitation along the channel are applied, and the time-history analysis method is used to carry out the dynamic time-history analysis. Through static analysis, the distribution of internal forces (axial force, shear force, in-plane moment, out-of-plane moment) along the main arch ring is studied. Through dynamic time history analysis, the displacement and internal force distribution of the main arch ring are studied, and the maximum displacement and the maximum internal force section position are determined respectively. The most unfavorable position of the main arch ring is determined by combining the static analysis results with the dynamic analysis results. (2) the single factor method is used to arrange the experiment, which changes the rise-span ratio, the form of arch axis, the arrangement and the density of bent frame. The finite element model is established, and the dynamic analysis is carried out, and the dynamic analysis results are combined with the static analysis results. By comparing the extreme values of internal force (axial force, shear force, in-plane moment, out-of-plane moment) and stress extremum of arch foot, the optimum rise-span ratio, the form of arch axis, the arrangement mode and the density of bent frame are determined respectively. (3) the experiment is arranged by orthogonal test method, the finite element model is established, and the dynamic analysis is carried out. The results of dynamic analysis and static analysis are combined, and the extreme value of internal force and the extreme value of stress of arch foot are analyzed by SPSS software, respectively. Finally, the optimal combination factor level, i.e. the optimal structural parameter combination, is determined by determining the primary and secondary order of the factors and considering the factors synthetically. The single factor method shows that the optimal rise-span ratio is 1 / 6, the optimal arch axis is catenary, the optimal arrangement is that the arch has no bent frame, and the optimal bent density is the original bent density. The results of orthogonal test show that the optimal arrangement of bent frames is the same as that of the single factor method, except for the seismic excitation in the transverse groove direction, and the other optimal structural parameters are the same as that of the single factor method.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV672.3;TV313

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