下穿式铁路框架桥轨道加固结构沉降与动力响应分析

发布时间：2018-02-28 13:33

本文关键词： 轨道加固桥涵顶进监测沉降动力特性　出处：《北方工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着我国交通线路网的不断完善,大量的公路与铁路的平交路口开始出现,为了提高交通线路运行的效率,需要将平交路口改造成立交路口。因为在平改立的工程中,下穿铁路施工可以不中断铁路运行,因此下穿式铁路框架桥是较多采用的改造形式。框架桥的顶进施工会引起对周围土体的扰动,使周围地层产生位移和变形,轨道加固系统本身也会产生受力变形,列车能否安全通过铁路线施工阶段需要进一步研究。针对这种情况,本文研究了框架地道桥顶进施工对轨道加固系统的影响。建立了土体一轨道加固结构的三维模型,对框架桥顶进施工中轨道加固结构的沉降进行了仿真计算分析。当开挖步距分别取0.75m、1.50m、2.25m、3.00m时,模拟框架桥的顶进施工过程,计算得出每步开挖后的钢轨和工字钢纵梁的沉降值,从而计算出在不同开挖步距下轨道加固系统的最大沉降值,并得到线路和轨道加固系统的沉降规律。对工程顶进过程进行沉降监测;根据实际工程中监测的数据,总结轨道结构沉降的规律,将监测数据与计算出的数据进行对比,监测的轨道沉降值与计算得出的轨道沉降值基本吻合,验证了计算结果的可靠性;从监测数据还可得出,纵梁的沉降值呈增加趋势,但满足规范要求;开挖步段出现了沉降波动,说明了预制箱型框架和轨道的不平整性开始显现出来。根据列车的实际轴重和轮间距,将列车简化为簧上质量;将钢轨模拟成梁单元,建立了符合工程实际的轮轨动力作用计算模型,分析结构体系在轮轨垂向荷载下的影响。通过对比不同顶进阶段的工字钢纵梁的振动位移和加速度,得出线路动力响应规律,随着框架桥顶进的深入,纵梁垂向位移幅值增大,加速度幅值减小。
[Abstract]:With the continuous improvement of China's traffic line network, a large number of highway and railway intersections have begun to appear. In order to improve the efficiency of traffic line operation, it is necessary to transform the horizontal intersection into an interchange, because in the project of leveling and setting up, The construction of the underpass railway can not interrupt the railway operation, so the frame bridge of the underpass railway is more commonly used. The jacking construction of the frame bridge will cause disturbance to the surrounding soil and cause the displacement and deformation of the surrounding strata. The track reinforcement system itself will also produce mechanical deformation, whether the train can safely pass through the railway line construction phase needs further study. In view of this situation, In this paper, the influence of the jacking construction of the frame tunnel bridge on the track strengthening system is studied, and the three-dimensional model of the soil-track strengthening structure is established. The settlement of track-strengthened structure during the jacking construction of frame bridge is simulated and analyzed. When the excavation step distance is 0.75mGW 1.50mt2.25mc3.00m respectively, the jacking construction process of the frame bridge is simulated, and the settlement values of the steel rail and I-beam after each step excavation are calculated. Thus the maximum settlement value of the track reinforcement system under different excavation steps is calculated, and the settlement law of the track and track reinforcement system is obtained. The settlement monitoring of the advance process of the project is carried out, and according to the monitoring data in the actual project, the settlement of the track reinforcement system is obtained. Summing up the rule of track structure settlement, comparing the monitoring data with the calculated data, the measured track settlement value basically coincides with the calculated track settlement value, which verifies the reliability of the calculated results. The settlement value of the longitudinal beam increases, but meets the requirements of the code. The settlement fluctuation in the excavation step shows that the unevenness of the precast box frame and track is beginning to appear. According to the actual axle load and wheel spacing of the train, The train is simplified to spring mass, the rail is simulated as a beam element, and the calculation model of wheel / rail dynamic action in accordance with engineering practice is established. By comparing the vibration displacement and acceleration of I-beam in different jacking stages, the dynamic response law of the line is obtained. The vertical displacement amplitude of the longitudinal beam increases with the advance of the roof of the frame bridge. The acceleration amplitude decreases.
【学位授予单位】：北方工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U213.2;U445

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