地震作用下沉管隧道节段接头剪力键的力学性能

基于有限元法结合黏弹性人工边界，将地震波输入转化为等效节点力，建立了基于波动理论的三维平面SV波入射方法.半空间算例证明了SV波入射方法及其数值实现的准确性，并在该地震波输入方法的基础上，考虑上覆海水对沉管隧道的静、动水压力，研究了港珠澳大桥沉管隧道节段接头剪力键的力学性能.研究结果表明:水平地震作用下也会产生竖向加速度，但竖向加速度值较小；地震作用下剪力键受力最大的是压应力，拉应力相对较小；剪力键拉应力主要集中在剪力键与沉管主体连接的部位，该处易产生拉伸裂缝，水平剪力键的破坏形式主要是拉伸破坏；接头剪力键的布设方向决定了剪力键根部的剪力分布，绝大部分剪力被布设方向和节段位移方向相一致的剪力键所承担.

Mechanical Properties of Shear Keys of Segment Joints in Immersed Tunnels Under Seismic Loading

On the basis of finite element method combined with viscous-elastic artificial boundary， the seismic wave input was transformed into equivalent node force， and a three-dimensional plane SV wave input method based on wave theory was established. The accuracy of seismic wave input method and the valid of the numerical analysis were proved by the half-space example. Then the mechanical properties of the shear keys of the segment joint in Hong Kong-Zhuhai-Macao Bridge immersed tunnel considering the static and dynamic water effects of the upper sea water were studied based on the established seismic wave input method. The results show that the vertical acceleration is also generated by horizontal earthquake， but the value of the vertical acceleration is small. The compressive stress is the largest stress on the shear key under earthquake， while the tensile stress is relatively small. Because the tensile stress of shear key is mainly concentrated on the locations where the shear key is connected with the main body of the immersed tunnel， tensile cracks are prone to occur. The main failure mode of horizontal shear keys is tensile failure. The setting direction of the shear key in the joint determines the shear distribution at the root of the shear key， and most of the shear forces are resisted by the shear key in the same direction with the displacement.