【作者】 贾庆稳；

【导师】 陈健云；

【作者基本信息】 大连理工大学 ， 水工结构工程， 2011， 硕士

【摘要】 我国的中西部是一个多山的地区,在将来的建设中必然出现大量山岭隧道工程。但是中西部尤其是西部地区具有全球最强烈的地壳活动和高地应力场,在这些地区修建隧道都和东部地区有明显的不同,尤其表现在地应力方面。随着隧洞工程埋深的增大,地应力必定增高。而西部多高山,隧洞的埋深自然也大,即很多隧道将处于高地应力状态。高的地应力环境下的地下隧道,在地震的扰动下,会更易发生破坏失稳。汶川大地震山岭隧道的震害表明,较大的水平地应力与地震荷载叠加会造成隧道更大的震害。对应高应力环境下的硬岩来说,地震的作用还有触发岩爆等其它破坏的可能。目前地下结构的抗震研究越来越多,但对高地应力、高地震烈度地区修建的隧道工程研究较少。而如前面所述,对我国西部的隧道开发,不可避免的会遇到高地应力的问题。故在高地应力情况下研究的地下结构的地震破坏情况成为西部建设的一项重要内容。本文在前人对地下结构抗震研究的基础上,基于无限元理论,使用直接积分解法,建立了二维隧道模型,充分考虑因各种误差所带来的地质条件不确定性因素及岩石非线性的影响,对山岭地区处于高地应力场下的深埋隧道进行了地震动荷载与静力荷载组合作用的动力时程分析。主要的内容和结论如下(1)考虑围岩与隧道开挖地下结构动力相互作用的影响,建立了无限元—有限元相互耦合作用的二维计算模型,对深埋岩体隧道地震动作用下的动力荷载激励进行数值研究,对不同工况下的隧道周围应力及位移进行对比分析,分析了地下深埋隧道的动力反应特点,研究了高地应力对深埋隧道结构综合动力分析的影响。(2)充分考虑岩体地质因素的不确定性影响,利用本文建立的数值模型对深埋隧道地震动作用下不同的岩体情况的动力响应进行数值研究。比较分析了水平侧压力系数对深埋隧道动力分析结果的影响。发现侧压力系数在深埋地下结构的动力响应中有着重要的意义。同时分析了岩体软弱破碎带及不同的岩石物理力学参数对深埋隧道地震动时程分析的影响,结果表明,对于同一埋深位置的隧道模型,地质因素不确定性因素对结果的影响显著,随着埋深的增加,地应力对地震动计算结果的影响也有较大的差异。更多还原

【Abstract】 There are numbers of mountains in the middle and western of China. Along with the implementation of the western development strategy, there is no doubt that more and more traffic facilities such as highways crossing mountains will be under construction which means lots of mountain tunnels will be on the scheme in the future. And it is much different from eastern areas when the mountain tunnels are built regarding the most intensive crust movement and the highest geo-stress field in the west of our country. The tunnels probably will be deep-buried and will be under high geo-stress conditions.Seismic response of underground structures has been widely studied recently, but the major subject of these researchers is on the behavior of shallow-buried tunnels or subways in the city. Obviously, the tunnels under high geo-stress conditions will be more easily destructed when earthquake occurs than shallow-buried tunnels with that the seismic analysis of tunnels under high geo-stress conditions become an unavoidable issue for the western development.Based on infinite theory, a two-dimensional calculation model is built to analyze the stress, displacement of the tunnel by using direct solving method. Considering the uncertainty of the geo-stress value due to inevitable error of sampling, several work conditions corresponding to each value are computed and compared.(1) The seismic response of deep-buried tunnels structure in hard rock was studied using two-dimensional large deformation infinite-finite coupled model, and effects of rock-structure interaction was considered by viscous boundary. In order to achieve reasonable both static and dynamic analysis results, the infinite element-finite element coupled boundary is adopted in the seismic performance. Using this simple and direct boundary conditions it can well solve the convergence problem between the static and dynamic calculation, and can also obtained good results in static excavation, without changing boundary when the calculation switch to dynamic analysis.(2) Effect of ground stress plays a more important role in the deep-buried tunnels than in shallow-buried tunnels. The concrete lining should be fully used to resist the dynamic deformation regarding that concrete materials can suffer more stress especially tensile stress than surrounding rocks in the vicinity of tunnels. Finally, it should be pointed out that consideration of the initial stress field and the influence of uncertainty of geo-stress is necessary and reasonable to get accurate deformation and force response of underground structures. The influence of deep-buried tunnels structure in hard rock on seismic response of free site is numerically investigated. In the case of building the tunnel structure and free site, the horizontal relative displacement and acceleration responses of tunnels structure has been analyzed briefly. Finally based on studying the relation of relative horizontal displacement of tunnels and the peak ground displacement relative to the bedrock at the free site, the peak ground displacement relative to the bedrock is a very effective design parameter of ground motion for evaluating the seismic response of underground structures.更多还原