某海底沉管隧道风塔及下部结构抗震性能分析

Seismic Performance Analysis of the Wind Tower and Substructure of a Submarine Immersed Tunnel

为研究某海底隧道风塔及下部结构体系在塑性阶段的损伤破坏形态及特点,探讨在多重荷载作用下弹塑性静动力响应对结构的影响,建立了沉管隧道风塔及下部结构的大型三维有限元模型。采用基于能量原理的混凝土塑性及损伤本构模型,借助大型有限元软件ANSYS及ABAQUS分别对结构进行不同地震条件下的动力时程分析,对比分析振型、层间位移角及较为完整的塑性损伤破坏系数曲线。结果表明:不同设防地震下,结构整体性良好,振型及层间位移角满足规范要求;不同罕遇地震下,该结构的混凝土塑性拉压损伤最大时刻均发生在20 s,主要破坏区域在风塔与人防井及下部立柱的接触位置,且拉伸破坏系数明显高于压缩破坏。本文的研究成果可以为类似近海沉管隧道工程抗震设计提供一定的依据与指导。

The effects of elastoplastic static and dynamic response on the structure under multiple loads are discussed to study the damage patterns and characteristics of the wind tower and substructure of an undersea tunnel at the plastic stage.A large three-dimensional finite element model of the wind tower and substructure of an undersea tunnel is established.On the basis of the concrete plasticity and its damage constitutive model,dynamic time history analysis of the structure under different seismic conditions is conducted by using ANSYS and ABAQUS,and the vibration mode,the story drift ratio,and the complete plastic damage destruction coefficient curve are compared and analyzed.Calculation results show that under different earthquakes,the integrity of the structure is good,and the vibration mode and story drift ratio can meet the specification requirements.Under different rare earthquakes,the maximum plastic tensile and compressive damage of the structure occurred at 20 s.The main damage area is in the contact position of the wind tower,human well,and lower column,and the stretch damage coefficient is significantly higher than the compression damage.The results can provide some basis and guidance for seismic design similar to offshore tunnel engineering.