高速铁路隧道洞外单开口缓冲结构抗震特性研究

发布时间：2019-05-15 03:56

【摘要】：随着我国高速铁路的迅猛发展,越来越多的高速铁路隧道将建设在高烈度地震区,缓冲结构作为隧道的洞口结构,易受到地震破坏而阻断交通。因此,对缓冲结构的抗震特性研究具有迫切的必要性。本文通过数值模拟方法,对不同形式隧道洞外单开口缓冲结构进行了三维动力分析,得出了顶部单开口、侧部单开口、条带式单开口以及间缝式单开口缓冲结构在剪切波下的地震响应规律和抗震特性,利用数值模拟方法对依此提出的洞口柔性连接和侧挡墙以及洞口柔性连接、侧挡墙以及联合使用柔性连接和带垫片侧挡墙三种抗减震措施的抗减震效果进行了分析与检验。得到的主要结论如下：(1)在剪切波作用下,隧道缓冲结构的加速度响应在竖直方向上表现出与普通地面结构相似的规律,结构上部的加速度响应更剧烈；在水平方向上,距洞口距离越远,拱顶、拱肩的加速度响应频率越高,峰值越大；拱腰加速度响应频率越高,峰值越小；而拱脚和仰拱的加速度响应几乎不发生变化。(2)在剪切波作用下,缓冲结构应力水平较静力作用下明显增大,仰拱最大主应力峰值明显大于其他部位。随距离洞口距离增加,仰拱、拱脚和拱腰的最大主应力值峰值曲线总体呈下降趋势；拱顶和拱肩的曲线相对平稳,变化不大。重点抗震设防部位应为：仰拱和拱脚部位,距洞口5m以内的拱腰部位以及侧部单开口附近的拱腰部位。(3)缓冲结构开口对其附近部位的加速度峰值和最大主应力峰值有不同程度的放大作用。总的来说,上部开口(间缝式单开口和顶部单开口)缓冲结构的抗震性能要优于侧部开口(条带式单开口和侧部单开口)缓冲结构。(4)洞口柔性连接会放大拱顶、拱肩、拱腰的加速度响应,但同时有效减小了结构重点设防部位仰拱、拱脚和拱腰的最大主应力峰值,起到了良好的减震效果。(5)侧挡墙限制了结构拱腰的加速度响应,但增大了拱顶、拱肩与拱腰在挡墙附近断面的应力水平,抗震效果不理想。(6)联合使用洞口柔性连接和带软质垫片的侧挡墙,显著减小了结构重点设防部位仰拱、拱脚和拱腰的最大主应力水平,而相比于单独使用洞口柔性连接,其对结构加速度响应亦起到了一定的限制作用,抗减震效果更佳良好。
[Abstract]:With the rapid development of high-speed railway in our country, more and more high-speed railway tunnels will be built in the area of high intensity earthquake. As the entrance structure of the tunnel, the buffer structure is vulnerable to earthquake damage and block traffic. Therefore, it is urgent to study the seismic characteristics of buffer structures. In this paper, the three-dimensional dynamic analysis of the single opening buffer structure outside the tunnel of different forms is carried out by means of numerical simulation, and the single opening at the top and the single opening on the side are obtained. The seismic response law and seismic characteristics of strip single opening and interslit single opening buffer structures under shear wave are studied by using numerical simulation method for flexible connection of opening and side retaining wall and flexible connection of entrance. The shock absorption effects of side retaining wall and flexible connection and gasket side retaining wall are analyzed and tested. The main conclusions are as follows: (1) under the action of shear wave, the acceleration response of tunnel buffer structure is similar to that of ordinary ground structure in vertical direction, and the acceleration response of the upper part of the structure is more intense; In the horizontal direction, the farther away from the hole, the higher the acceleration response frequency of arch roof and arch shoulder, the greater the peak value, the higher the acceleration response frequency of arch waist, the smaller the peak value. However, the acceleration response of arch foot and inverted arch has little change. (2) under the action of shear wave, the stress level of buffer structure is obviously higher than that under static action, and the peak value of maximum principal stress of inverted arch is obviously higher than that of other parts. With the increase of the distance from the entrance, the peak curve of the maximum principal stress of inverted arch, arch foot and arch waist shows a downward trend, while the curve of arch roof and arch shoulder is relatively stable and does not change much. The key seismic fortification parts should be: inverted arch and arch foot, The arch waist within 5 m from the hole and the arch waist near the single opening in the side. (3) the acceleration peak value and the maximum principal stress peak value of the buffer structure are magnified to varying degrees. Generally speaking, the seismic performance of the upper opening (interslit single opening and top single opening) buffer structure is better than that of the side opening (strip single opening and side single opening) buffer structure. (4) the flexible connection of the opening will enlarge the arch roof and arch shoulder. The acceleration response of the arch waist, but at the same time effectively reduces the maximum principal stress peak value of the inverted arch, arch foot and arch waist in the key fortification part of the structure, and has a good shock absorption effect. (5) the side retaining wall limits the acceleration response of the arch waist of the structure. However, the stress level of arch roof, arch shoulder and arch waist near the retaining wall is increased, and the seismic effect is not ideal. (6) the combined use of flexible connection at the mouth of the hole and the side retaining wall with soft gasket significantly reduces the inverted arch in the key fortification part of the structure. Compared with the flexible connection of the opening alone, the maximum principal stress level of the arch foot and the arch waist also plays a certain limiting role in the acceleration response of the structure, and the damping effect is better.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U453.1

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