考虑桩-土相互作用的某海底隧道岸边段结构抗震性能分析研究

Seismic Behavior of Bank Section of a Submarine Tunnel Considering Pile-Soil Interaction

摘要:

随着我国沿海及沿江城市交通发展的需要，水下沉管隧道工程建设的迫切性不断提高，其抗震性能也是备受关注的重要内容。以某海底隧道建设工程隧道北岸岸边段为工程研究背景，基于ANSYS软件建立沉管隧道-土体-桩基-沉箱三维有限元模型，管节接头采用COMBIN39单元模拟止水带和剪力杆，通过非线性F-D曲线模拟其物理力学性能，采用无厚度接触单元对桩-土间的接触效应进行描述，在外边界处设置黏弹性人工边界来反映远场地基辐射效应。计算结果表明：在罕遇地震作用下，沉箱接口处具有较大的应力，主要是接口处材料发生变化，容易出现应力集中现象；管节接头处止水带上部位移比下部位移大，更容易发生破坏。可为海底隧道岸边段及类似结构的抗震安全评价及优化设计提供参考。

Abstract:

With the development of urban transportation along the coast and rivers in China, the urgency of constructing submerged immersed tunnels is constantly increasing, and their seismic performance also becomes an important content of concern. Taking the northern bank section of a submarine tunnel project as the research object, a three-dimensional finite element model of immersed tunnel-soil-pile foundation-caisson was established based on ANSYS software. The water stop and shear bar were simulated by COMBIN39 element, and their physical and mechanical properties were simulated by non-linear F-D curve. The contact effect between pile and soil was described by thickness-free contact element, and the radiation effect of far-field foundation was reflected by setting viscoelastic artificial boundary. The calculation results showed that under the action of rare earthquakes, the caisson interface has a large stress due to the change of interface material and the consequent stress concentration phenomenon. The displacement of upper water stop at tube joint is larger than that of lower water stop, so it is easier to be damaged. It can provide a reference for seismic safety evaluation and optimal design of immersed tunnels and similar structures.