高速铁路桥隧搭接结构地震动力响应试验研究

发布时间：2018-07-26 18:03

【摘要】：近年来,随着中国经济的腾飞,我国西部地区高速铁路建设得到了迅猛发展。由于西部地区地形条件复杂,因而,在山岭地区的高速铁路建设中,常采用桥梁与隧道相互搭接的连接形式。由于我国西部地区多为地震灾害频发地段,建在软弱围岩中的桥隧搭接结构极易遭受严重破坏。桥隧搭接结构在强烈地震作用下,极易受到严重的损伤或破坏,并将造成人员伤亡和巨大的经济损失。因此,开展对桥隧搭接段的地震动力响应及抗震减灾措施的研究,具有重要的理论意义和广阔的工程应用前景。本文依托国家自然科学基金项目“基于损伤累积效应的桥隧搭接结构地震动力响应研究”(编号:51408617),以沪-昆高速铁路中某分离式洞口桥隧搭接工程为研究背景,对高速铁路分离式桥隧搭接结构开展了相关的试验和理论研究。通过大型振动台试验和相应的理论分析,系统地探索了分离式洞口桥隧搭接段的地震动力响应规律。在此基础上,揭示了分离式洞口桥隧搭接段的地震破坏机理。本文的主要研究工作内容和取得的研究进展及创新结论如下。一、本文的主要研究工作内容1)基于相似理论,确定了主要物理量的相似常数,并依据试验要求与研究目标,设计并制作完成了相似比为1:30的高速铁路分离式桥隧搭接结构模型;通过配比试验,确定了模型的混凝土相似材料参数;针对振动台试验中模型箱体边界的反射问题,采取了有效的隔离消能措施,减少或消除边界反射效应对试验结果的影响。2)根据振动台对地震波输入的适应性和可靠性,分别选取了 EI Centro波、汶川波及Kobe波等作为试验的输入地震波,并对未满足振动台适应性要求的输入波进行了滤波处理。在综合考虑地震波的类型、激振强度、加载方向及顺序等多因素影响的基础上,提出了合理的地震波加载方案。通过加载试验,分别测定了在不同的工况条件下,分离式桥隧搭接段各部位的加速度、动位移和动应变等。3)通过对大型振动台模型试验结果分析,探索了高速铁路分离式桥隧搭接段在各种工况条件下的加速度、动位移和动应变的地震动力响应规律;研究了分离式桥隧搭接段在地震作用下隧道与桥台之间的相互影响规律;探讨并分析了分离式桥隧搭接的地震破坏机理及其抗震设防措施。二、本文所取得的主要研究进展及创新结论通过试验和理论研究,本文探明了在不同加载方向的地震波、不同激振强度的地震波和不同类型的地震波作用下,对桥隧搭接结构的加速度、动位移和动应变的影响规律;揭示了分离式桥隧搭接结构的地震破坏机理;提出了分离式桥隧搭接结构的抗震设防措施。1)不同加载方向的地震波对加速度、动位移和动应变的影响规律①在不同方向的地震波作用下,纵向地震波对桥隧搭接段的影响最大,竖向地震波对其影响最小。纵向或者横向地震波的参与对竖向地震波作用效果的影响较大,但竖向地震波对纵向或者横向水平地震波的作用效果的影响均较小。桥隧搭接段在地震荷载下的加速度动力响应,主要由水平方向的纵向波和横向波起主导作用。②在不同方向地震波作用下,桥隧搭接段中出现最大纵向动位移的位置不同。在纵向地震波作用下,桥端位置处的纵向动位移值最大;在横向和竖向地震波作用下,扩大段衬砌拱顶位置处的纵向动位移值最大。③在X向、XY双向和XZ双向加载条件下,扩大段近洞口衬砌上各测点动应变峰值,从拱脚到拱顶随高程呈现出先增大后减小的趋势。扩大段远洞口衬砌上各测点动应变峰值,从拱脚到拱顶随高程增大而增大。④在有沿隧道轴向的地震波作用下,扩大段近洞口截面衬砌的动应变比扩大段远洞口截面衬砌的动应变大。因此,对扩大段近洞口处衬砌的抗震设防需要更加引起重视。2)不同激振强度的地震波对加速度、动位移和动应变的影响规律①桥隧搭接段各关键测点的横向和纵向加速度峰值随地震波激振强度的增大而增大,其加速度放大系数也均随地震波激振强度的增大而增大。桥隧搭接段各关键测点竖向加速度峰值随地震波激振强度的增大而增大,但加速度放大系数随地震波激振强度的增大而呈现出先增大后减小的趋势。②不同激振强度作用下,扩大段衬砌各测点动位移随激振强度的增大而增大。其中,桥端的动位移最大。桥台顶和标准段仰拱的竖向动位移随激振强度增大而增大。其中,在桥台顶的动位移的增幅更大。标准段顶部土体和扩大段仰坡土体的竖向动位移也随激振强度增大而增大。在Amax小于0.4g时,标准段顶部土体动位移比扩大段仰坡土体动位移大,但二者的增大速率相近。在Amax大于0.4g时,扩大段仰坡土体位移大幅增大,动位移值超过标准段顶部土体的动位移值。③桥隧搭接段扩大段的1-1截面和1-2截面衬砌各测点的动应变的正、负峰值随激振强度的增大而增大。在1-1截面(近洞口段)的衬砌中,拱肩位置处的动应变增长速率最大。在1-2截面(远洞口段)的衬砌中,拱腰位置处的动应变增长速率最大。这一规律说明,在扩大段中,近洞口段衬砌和远洞口段衬砌对地震强度的敏感部位是不一样的。3)不同类型的地震波对加速度、动位移和动应变的影响规律①桥隧搭接段在不同地震波作用下,各测点的加速度峰值及加速度放大系数变化趋势相近。横向加速度最大峰值均出现在桥台顶部位置,横向加速度最小峰值出现在桥梁跨中位置;竖向最大加速度峰值及其最大放大系数均出现在桥梁跨中位置。地震波类型对桥隧搭接段各位置的加速度峰值和加速度放大效应影响不大。②在EI Centro波、San Fernando波和汶川波三种地震波中,EI Centro波对桥隧搭接段的Y向和Z向的动位移影响最大。而在EI Centro波、Kobe波和Taft波中,Taft波对桥隧搭接段的Y向和Z向的动位移影响最大。③在EI Centro波(EI)、San Fernando(SF)波和汶川波(WC)等三种不同类型的地震波作用下,在扩大段衬砌近洞口断面和远洞口断面两个截面中,各测点的动应变发展趋势基本一致。即两个截面的动应变均随高程的增大而先增大后减小,在拱腰处的正、负动应变峰值最大。这一规律说明,地震波类型对桥隧搭接段的动应变影响较小。综上所述,本文探索了高速铁路分离式桥隧搭接段在各种工况条件下的加速度、动位移和动应变的地震动力响应规律;研究了分离式桥隧搭接段在地震作用下隧道与桥台之间的相互影响规律;并最终揭示了高速铁路分离式桥隧搭接结构在不同地震作用下的动力响应机理。研究结果不但对探索桥隧搭接结构的地震响应规律具有重要的理论意义,也对桥隧搭接段的设计和施工,特别是对抗震设防具有重要的指导意义。
[Abstract]:In recent years, with the rapid development of China's economy, the construction of high speed railway in Western China has been developed rapidly. Because of the complex terrain conditions in the western region, the connecting form of bridges and tunnels is often used in the construction of high speed railway in the mountain area. Because most of the western region of China is frequent in earthquake disaster, it is built in weakness. The bridge and tunnel connecting structure in the surrounding rock is extremely vulnerable to serious damage. The bridge and tunnel joint structure is extremely vulnerable to severe damage or damage under the action of strong earthquake, and will cause casualties and huge economic losses. Therefore, it is of great theoretical significance to study the seismic dynamic response and earthquake disaster mitigation measures of the bridge and tunnel junction section. Based on the National Natural Science Foundation Project "study on seismic dynamic response of bridge and tunnel construction based on damage accumulation effect" (numbered: 51408617), this paper takes a separate bridge and tunnel connecting project in Shanghai Kun high speed railway as the research background, and carries out a correlation on the separation type bridge and tunnel structure of high speed railway. On the basis of the large-scale shaking table test and the corresponding theoretical analysis, the seismic dynamic response law of the bridge and tunnel section of the separation type tunnel is systematically explored. On this basis, the seismic failure mechanism of the separation section of the bridge and tunnel is revealed. The main research work and the progress of the research and the innovation of this paper are made in this paper. First, the main research work of this paper 1) based on the similarity theory, the similarity constants of the main physical quantities are determined, and according to the test requirements and research objectives, a high-speed railway separation bridge and tunnel joint structure model with similar ratio of 1:30 is designed and made, and the similar material parameters of the model concrete are determined by the ratio test. In view of the reflection of the boundary of the model box in the shaking table test, the effective isolation measures are taken to reduce or eliminate the influence of the boundary reflection effect on the test results.2). According to the adaptability and reliability of the seismic wave input, the EI Centro wave, the Wenchuan wave and the Kobe wave are selected as the input seismic waves, respectively. The input wave which is not satisfied with the adaptability of the shaking table is filtered. On the basis of many factors such as seismic wave type, excitation intensity, loading direction and order and so on, a reasonable seismic wave loading scheme is proposed. By loading test, the separate bridge and tunnel lap section under different working conditions is respectively measured. The acceleration, dynamic displacement and dynamic strain of.3), through the analysis of the large shaking table model test results, explore the acceleration, dynamic displacement and dynamic response of the separate bridge and tunnel section of high speed railway under various working conditions, and study the separation type bridge and tunnel section between the tunnel and the abutment under the earthquake action. The mechanism of seismic failure and its seismic fortification measures are discussed and analyzed. Two, the main research progress and innovation conclusions obtained in this paper are through experimental and theoretical research. The seismic waves in different loading directions, seismic waves with different excitation intensity and different types of seismic waves are explored in this paper. The effect of acceleration, dynamic displacement and dynamic strain on the overlapping structure of bridge and tunnel, the seismic failure mechanism of the separate bridge and tunnel structure is revealed. The influence of seismic wave on the acceleration, dynamic displacement and dynamic strain in different direction of loading direction of the separate bridge and tunnel structure.1) Under the action of seismic wave, the longitudinal seismic wave has the greatest influence on the bridge and tunnel lap section, and the vertical seismic wave has the smallest influence on it. The vertical or lateral seismic waves have great influence on the effect of vertical seismic wave, but the effect of vertical seismic wave on the effect of vertical or horizontal horizontal seismic waves is smaller. Under the action of seismic waves in different directions, the maximum longitudinal displacement in the bridge and tunnel section is different. Under the action of longitudinal seismic waves, the longitudinal displacement of the bridge end is maximum, and under the action of lateral and vertical seismic waves, it expands. Under the condition of X direction, XY bi-directional and XZ bi-directional loading, the peak value of dynamic strain of each measuring point on the lining of the tunnel is extended from the arch foot to the vault with the elevation. The peak of the dynamic strain of each point on the lining of the far hole is expanded from the arch foot to the vault with Gao Chengzeng. Under the action of the seismic wave along the axial direction of the tunnel, the dynamic strain of the section lining of the near hole section of the extended section is larger. Therefore, the seismic fortification of the lining at the near hole in the extended section needs to pay more attention to the.2) the seismic waves of different excitation intensity to the acceleration, the dynamic displacement and the dynamic strain. The lateral and longitudinal acceleration peaks of the key points of the bridge and tunnel section increase, and the acceleration amplification coefficient increases with the increase of the intensity of the seismic wave excitation. The peak acceleration of the key points of the bridge and tunnel section increases with the increase of the intensity of the seismic wave excitation, but the acceleration is increased. The amplification factor increases first and then decreases with the increase of the intensity of the seismic wave excitation. Under the action of different exciting strength, the dynamic displacement of the measured points of the expanded section increases with the increase of the exciting strength. The increase of dynamic displacement at the top of the abutment is greater. The vertical dynamic displacement of the soil at the top of the standard section and the elevation slope also increases with the increase of the excitation strength. The dynamic displacement of the soil at the top of the standard section is larger than that of the enlarged section on the elevation slope when Amax is less than 0.4g, but the increase rate of the two is similar. When the Amax is greater than 0.4g, the elevation of the slope soil body is enlarged. The displacement value increases greatly and the dynamic displacement value exceeds the dynamic displacement of the soil at the top of the standard section. 3. The positive strain of the 1-1 section and the 1-2 section lining of the bridge and tunnel segment expansion section increases with the increase of the exciting strength. In the lining of the 1-1 section (near hole section), the growth rate of the dynamic strain at the position of the arch shoulder is the largest. In the 1-2 cross section. In the lining of the long hole, the growth rate of the dynamic strain at the position of the arch waist is the largest. This rule shows that in the expansion section, the sensitive parts of the lining and the far hole lining for the seismic intensity are different.3) in the expansion section, the influence of different types of seismic waves on the acceleration, the dynamic displacement and the dynamic strain of the bridge is different. Under the action of seismic wave, the peak acceleration and acceleration magnification coefficient of each measuring point have a similar trend. The maximum peak value of the lateral acceleration appears at the top of the abutment. The minimum peak value of the lateral acceleration appears in the middle span of the bridge. The maximum vertical peak acceleration and the maximum number of magnification systems all appear in the middle span of the bridge span. In the three seismic waves of EI Centro wave, San Fernando wave and Wenchuan wave, EI Centro wave has the greatest influence on the dynamic displacement of Y direction and Z direction in the lap section of bridge and tunnel, while in EI Centro wave, Kobe wave and Taft wave. Under the action of three different types of seismic waves, such as EI Centro wave (EI), San Fernando (SF) wave and Wenchuan wave (WC), the dynamic strain development trend of each test point is basically the same in the two sections of the near hole section and the far hole section. That is, the dynamic strain of the two sections increases first and then decreases with the elevation. The maximum negative dynamic strain peak at the arch waist is the largest. This rule shows that the type of seismic wave has little influence on the dynamic strain of the bridge and tunnel section. In summary, the acceleration, dynamic displacement and dynamic response of the separate bridge and tunnel section of high speed railway are explored in this paper, and the separation type bridge and tunnel are studied. The interaction law of the overlapping section between the tunnel and the abutment under the earthquake action, and finally reveals the dynamic response mechanism of the separation type bridge and tunnel structure under the action of different earthquakes. The results of the study not only have important theoretical significance for exploring the seismic response law of the bridge and tunnel structure, but also the design of the bridge and tunnel lap section. And construction, especially for seismic fortification.
【学位授予单位】：中南林业科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U442.55;U211.9;U452.28

【相似文献】