劣化衬砌结构地震响应分析

发布时间：2018-06-24 15:04

本文选题：山岭隧道 + 劣化度　；参考：《西南交通大学》2015年硕士论文

【摘要】：我国幅员辽阔,山脉众多,地形地质条件非常复杂,这种情况在我国西部地区显得尤为明显。为了响应国家西部大开发的战略,大力修建通往西部地区的交通线已经成为发展我国西部地区的先决条件。除过公路运输、航空运输外,铁路运输由于其成本低廉、运量大、速度快,已经成为发展西部地区的主要交通方式。在打通通往西部地区的铁路线上,众多山岭隧道已经被修建完成。但是,地质条件的复杂性使得山岭隧道更容易遭受病害袭扰且大多数山岭隧道都是带“劣”运营。不仅如此,西部地区也是我国地震高发地带。本文主要着重于劣化隧道在地震荷载作用下的地震动力响应研究。本文主要完成工作如下：(1)隧道模型尺寸的确定。通过建立6倍、7倍、8倍、9倍、10倍洞径的隧道模型,在模型底部施加横向(X向)地震荷载(以应力形式),分别分析各个工况下隧道的动力响应。结果表明,当横向边界尺寸大于等于8倍洞径时,横向边界尺寸对动力响应产生的影响逐渐趋于稳定。因此,为了降低边界对隧道动力响应结果的影响,建议取用8倍洞径或以上作为模型的横向尺寸。(2)基于动力强度折减法,运用FLAC3D分析劣化位于隧道不同位置时的隧道力学机理以及模型的安全性。进而分析劣化范围不同时的隧道力学机理以及模型的安全性。当劣化分别位于拱顶、边墙中部、仰拱中心时,模型安全系数均为0.85；模型安全系数随着拱顶劣化范围的扩大呈现出逐渐减小的趋势。(3)第一点,基于动力强度折减法,运用FLAC3D分析不同洞型下劣化隧道结构的安全性与稳定性。结果表明,圆形隧道安全性最好,三心圆次之,直墙拱隧道安全性最差。第二点,基于动力强度折减法,运用FLAC3D分析不同围岩级别下,劣化隧道结构的安全性与稳定性。结果表明,围岩情况越好,劣化隧道的安全性也越好。第三点,基于动力强度折减法,运用FLAC3D来分析不同埋深下,劣化隧道结构的力学机理以及模型的安全性。结果表明,2倍洞径到5倍洞径埋深下,埋深越深,劣化隧道的安全性越好；埋深达到8倍洞径时,其安全性较2倍洞径埋深和5倍洞径埋深有所降低。第四点,基于动力强度折减法,运用FLAC3D来分析不同地震波持时下,劣化隧道结构的安全性与稳定性。结果表明,在同一个地震波持时基础上,随着劣化度的增加,隧道结构的安全系数越小；地震波持时越长,衬砌结构所遭受的震害也越大。
[Abstract]:China has a vast territory, numerous mountains and complicated topography and geology, which is especially obvious in the western part of our country. In order to respond to the strategy of China's western development, it has become a prerequisite for the development of China's western region to build a transportation line leading to the western region. In addition to road transportation and air transportation, railway transportation has become the main mode of transportation in the western region because of its low cost, large volume and high speed. Many mountain tunnels have been built on the railway to the west. However, the complexity of geological conditions makes mountain tunnels more susceptible to disease and most mountain tunnels are "poorly" operated. Not only that, the western region is also a high incidence of earthquakes in China. This paper focuses on the seismic dynamic response of the degraded tunnel under seismic load. The main work of this paper is as follows: (1) the determination of tunnel model size. By establishing a tunnel model of 6 times 7 times 8 times and 9 times 9 times 10 times diameter, the lateral (X) seismic load (in the form of stress) is applied to the bottom of the model, and the dynamic response of the tunnel under each working condition is analyzed respectively. The results show that when the transverse boundary size is greater than or equal to 8 times the diameter of the hole, the influence of the transverse boundary size on the dynamic response tends to stabilize gradually. Therefore, in order to reduce the influence of the boundary on the dynamic response of the tunnel, it is suggested that 8 times diameter or more of the tunnel should be used as the transverse dimension of the model. (2) based on the dynamic strength reduction method, The mechanism of tunnel mechanics and the safety of the model are analyzed by FLAC3D. Furthermore, the mechanism of tunnel mechanics and the safety of the model are analyzed. The model safety coefficient is 0.85 when the deterioration is located in the arch roof, the middle of the side wall and the center of the inverted arch, and the model safety coefficient decreases gradually with the expansion of the deterioration range of the arch. (3) the first point is based on the dynamic strength reduction method. Using FLAC3D to analyze the safety and stability of the deteriorated tunnel structure under different hole types. The results show that the safety of circular tunnel is the best, that of triaxial tunnel is the second, and that of straight wall arch tunnel is the worst. Secondly, based on the dynamic strength reduction method, FLAC3D is used to analyze the safety and stability of the degraded tunnel structure under different surrounding rock levels. The results show that the better the surrounding rock condition, the better the safety of the deteriorated tunnel. Thirdly, based on the dynamic strength reduction method, FLAC3D is used to analyze the mechanics mechanism and the safety of the model. The results show that the deeper the tunnel is, the better the safety of the tunnel is, and when the depth of the tunnel reaches 8 times the depth of the tunnel, the safety of the tunnel is lower than that of the two times the diameter of the tunnel and the depth of 5 times the diameter of the tunnel. Fourthly, based on the dynamic strength reduction method, FLAC3D is used to analyze the safety and stability of the degraded tunnel structure under different seismic waves. The results show that, on the basis of the same seismic wave duration, with the increase of deterioration degree, the safety factor of tunnel structure is smaller, and the longer the seismic wave duration, the greater the damage to the lining structure.
【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】：U456

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