为避免近场斜入射地震波对海底沉管隧道造成灾难性后果，对沉管隧道及其剪力键在斜入射地震作用下的动力响应规律进行深入研究。首先，基于时域有限元方法并结合黏弹性人工边界，将地震波转换为模型边界节点的等效节点力，建立基于波动理论的三维平面SV波斜入射方法，并采用半空间算例验证该方法的准确性； 然后，在该地震波输入方法的基础上，利用ABAQUS软件建立土体-沉管隧道节段三维精细化有限元模型，研究地震SV波斜入射作用下不同入射角度对沉管隧道及其剪力键动力响应的影响。研究结果表明： 1）当SV波入射角接近临界角时，斜入射对隧道竖向和纵向响应达到最大值，水平响应与入射角呈反比关系； 2）斜入射会使结构中对称部位产生非对称剪力，剪力键的剪力承担比也发生改变； 3）剪力键根部易产生拉伸裂缝，端角也可能因应力集中而产生局部破坏。
The nearfield oblique incident seismic
waves might cause a catastrophe in submarine immersed tunnels. Thus, examining
the dynamic response patterns of immersed tunnels and their shear keys under
oblique incident earthquakes is imperative. First, the seismic wave is
converted into the equivalent node force of the model boundary node based on
the finite element method and the viscoelastic artificial boundary. This
process establishes the threedimensional plane SV wave
oblique incidence method based on wave theory and validates its accuracy
through a halfspace example. Then, based on the
seismic wave input method, a threedimensional refined
finite element model of a soilimmersed tunnel is
established using ABAQUS software. The influence of different SV wave incident
angles on the dynamic response of an immersed tunnel and its shear key is
studied. The results indicate the following: (1) When the incident angle of the
SV wave is close to the critical value, the vertical and longitudinal responses
of the tunnel reach the maximum. The horizontal response is inversely
proportional to the incident angle. (2) The oblique incidence will cause
asymmetric shear force in the symmetrical parts of the structure, changing the
shearbearing ratio of the shear keys. (3) The root of
the shear key is prone to tensile cracks, and the end angle might cause local
damage due to compressive stress concentrations.
