P波斜入射角对沉管隧道地震响应的影响

Analysis on Seismic Responses of Immersed Tunnel Under Inclined P Waves

为了研究P波斜入射对沉管隧道地震响应的影响,以港珠澳大桥沉管隧道为工程背景,考虑上覆海水与海床、沉管隧道之间耦合作用,采用粘弹性边界和等效力的地震荷载输入方式,利用ADINA软件建立三维有限元模型进行地震响应分析。分析入射角为0°、20°、40°、50°、60°时P波对沉管隧道环向应力峰值(正应力峰值、剪应力峰值)和位移峰值的影响,结果表明:入射角为40°时,沉管隧道应力峰值最大;入射角为0°—40°时,隧道的应力峰值逐渐增大,入射角为40°—60°时,隧道的应力峰值逐渐减小;隧道截面4个转角处及隔墙与顶板、底板的连接处为隧道剪应力峰值最大处;隧道截面左侧剪应力峰值远大于右侧;隧道顶板正应力峰值最大,顶板的正应力峰值大约为底板的2倍;隧道截面左侧位移峰值远大于隧道截面右侧。

To study the seismic response of immersed tunnel under inclined P waves, we carried out a series of simulation analysis. In this paper, we presented 3 D analytical models of immersed tunnel which is based on the Hong Kong-Zhuhai-Macao Bridge immersed tunnel taking account of viscous-spring artificial boundary and solid-fluid interaction modeled by ADINA, and analyzed the seismic response of immersed tunnel under P waves with angle of incidence 0°, 20°, 40°, 50°, 60°. It is shown that peak value of stress of tunnel under P waves with angle of incidence 40° reached maximum. The peak value of stress of tunnel had shown a magnifying trend when P-wave angle of incidence 0° increased to 40° and a decreasing trend when P-wave angle of incidence 40° increased to 60°. The larger peak stress point on the immersed tunnel takes place in the four corners of the tunnel and the connection between the partition wall and the bottom plate and the roof. The peak value of shear stress of left side of tunnel cross section is larger than the right side of the tunnel section. The largest peak value of normal stress of tunnel appears on roof, and the peak value of normal stress of roof is about 2 times of on the floor. The peak value of displacement of left side of tunnel cross section is larger than the right side of the tunnel section.