跨海减震隧道工程结构的地震动稳定分析

发布时间：2018-02-11 14:30

本文关键词： 减震跨海隧道渗流流-固耦合地震稳定安全系数　出处：《兰州理工大学》2014年硕士论文　论文类型：学位论文

【摘要】：为方便人们出行、促进区域经济发展,利用跨海隧道将远离陆地的各个岛屿或陆地连接起来,是世界各国人民长久以来的梦想。随着现代化的工程地质勘察、工程材料技术和施工技术的发展,这些梦想已在多处得到实现。相较于其他形式的隧道如陆上隧道,跨海隧道有着更为复杂的地质环境。海底存在着复杂的地貌；跨海隧道需要在一定深度海水之下的岩体中开挖,有时候海水深度会非常深,其围岩要承受巨大的水压力；海底地质条件普遍较差,风化覆盖层较厚,围岩多为饱和中风化和微风化裂隙岩体,其中存在着较高的孔隙水压和渗透压。因此跨海隧道跟陆上隧道相比,更容易出现失稳破坏。随着经济的快速发展和人们工作生活节奏的加快,跨海隧道必将在未来的交通运输当中起到决定性作用。因此,进行复杂地质环境下跨海隧道的地震动稳定研究,定量估计跨海隧道的地震动安全系数具有重要的理论和工程实际意义。本文以胶州湾跨海隧道为工程背景,在现有关于陆上隧道地震动稳定研究以及跨海隧道静力稳定分析的基础上,利用ADINA软件分别建立结构模型和流体模型。考虑粘弹性人工边界以及地震、渗流的影响,通过两个模型进行流-固耦合动力分析,研究海水深度、覆岩厚度和渗透系数对跨海隧道动力稳定安全系数的影响以及跨海隧道塑性区的变化规律。同时研究了有无减震层时跨海隧道围岩结构安全系数的变化情况,从而得到了设置减震层对跨海隧道安全系数的影响。研究结果表明： (1)渗流和双向地震作用下,跨海隧道的塑性区最先出现在跨海隧道两侧拱脚、拱肩周边部位,拱顶部位没有出现塑形区,较为安全。 (2)在海水深度一定的情况下,覆岩厚度越大,塑性区发展愈明显,安全系数越小；在覆岩厚度一定的情况下,海水深度越大,塑性发展愈明显,安全系数越小,但变化幅度不大；渗透系数对围岩塑形区发展和地震动安全系数的影响不明显。 (3)设置减震层可以提高跨海隧道结构在地震作用下的安全系数,能够起到良好的减震效果。 (4)覆岩厚度越厚,设置减震层对跨海隧道在地震作用下的安全系数提高越少；海水深度和渗透系数的变化对由于设置减震层而导致的安全系数提高幅度影响不大。 (5)覆岩厚度的变化较之海水深度和渗透系数对跨海隧道在地震作用下安全系数的影响更大。
[Abstract]:In order to facilitate people's travel and promote regional economic development, the use of cross-sea tunnels to connect islands or land far from land has long been the dream of the peoples of the world. With the development of engineering material technology and construction technology, these dreams have been realized in many places. Cross-sea tunnels have a more complex geological environment than other types of tunnels such as onshore tunnels. There are complex landforms on the seabed; cross-sea tunnels need to be excavated in rock masses below a certain depth of seawater. Sometimes the depth of seawater is very deep, and its surrounding rock has to bear huge water pressure. The geological conditions of seabed are generally poor, the weathering overburden is thicker, and the surrounding rock is mostly saturated with weathering and breezy fissured rock mass. There are high pore water pressure and osmotic pressure among them, so cross-sea tunnel is more prone to unstable failure than onshore tunnel. With the rapid development of economy and the rapid pace of people's work and life, cross-sea tunnel will play a decisive role in the future transportation. It is of great theoretical and practical significance to quantitatively estimate the seismic safety factor of cross-sea tunnels. This paper takes Jiaozhou Bay cross-sea tunnel as the engineering background, based on the existing research on the ground motion stability of the onshore tunnel and the static stability analysis of the cross-sea tunnel. The structural model and fluid model are established by using ADINA software. Considering the influence of viscoelastic artificial boundary, earthquake and seepage, the fluid-solid coupling dynamic analysis is carried out through the two models, and the depth of seawater is studied. The influence of overburden thickness and permeability coefficient on the dynamic stability safety factor of cross-sea tunnel and the variation rule of plastic zone of cross-sea tunnel are studied, and the variation of safety factor of surrounding rock structure of cross-sea tunnel with or without seismic absorption layer is studied. The influence of the damping layer on the safety factor of cross-sea tunnel is obtained. The results show that:. 1) under the action of seepage and bi-directional earthquake, the plastic zone of cross-sea tunnel first appears on the two sides of cross-sea tunnel arch foot, arch shoulder peripheral part, arch top part no plastic area, relatively safe. (2) when the depth of seawater is constant, the larger the overlying rock thickness, the more obvious the plastic zone development is, and the smaller the safety coefficient is, and when the overlying rock thickness is constant, the greater the seawater depth is, the more obvious the plastic development is, and the less the safety factor is. The influence of permeability coefficient on the development of surrounding rock molding area and the safety factor of ground motion is not obvious. 3) the safety factor of the cross-sea tunnel structure can be improved by setting the damping layer, and it can play a good damping effect. 4) the thicker the overburden is, the less the safety coefficient of cross-sea tunnel is increased by setting the damping layer, while the variation of sea water depth and permeability coefficient has little effect on the increase of safety coefficient caused by the installation of the damping layer. The variation of overburden thickness has greater influence on the safety factor of cross-sea tunnel under earthquake than the depth of sea water and permeability coefficient.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U452.28;U459.5

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