水域隧道地震响应分析

Influencing factors for seismic responds of a subsea tunnel

本文基于Biot动力固结理论和弹性动力学理论,考虑海床(土壤)的两相性、黏弹性人工边界及流(水)-固耦合作用,建立了隧道-土-流体相互作用的力学模型,讨论了P波作用下有无水的情况以及水深、水域隧道埋深、海床土性质和地震波入射角等因素对隧道及其周围海床应力的影响。结果表明:隧道周围海床土的孔隙水压力和隧道内应力随着水深的增加而增加;地震波特性和海床土特性对隧道的内应力和海床土的孔隙水压力均有较大的影响;海床土的渗透性和隧道埋深对隧道的内应力影响较小,而对隧道周围海床土的孔隙水压力影响较大;地震动的入射角对隧道的内应力和隧道附近土层的孔隙水压力均有较大影响。

Under the action of an earthquake,a sea tunnel is subjected to hydrodynamic pressure,so it is of great significance to study the dynamic response of sea tunnel under the combined action of earthquake and hydrodynamic pressure.Based on Biot’s theory of dynamic consolidation and elastodynamics theory,this paper established a mechanical model of tunnel-soilfluid interaction by considering the two-phase property of seabed(soil)and the viscoelastic artificial boundary and the action of fluid(water)-structure interaction,and then discussed how the tunnel and its surrounding seabed are affected by the condition with or without water,and the depth of water,the buried depth of the tunnel,the nature of the seabed soil and change of incident angle.The results show that:①the pore water pressure of the seabed soil and the internal stress of the tunnel increase with water depth increasing;②different seismic wave and seabed soil characteristics have a great impact on the internal stress of the tunnel and the pore water pressure;③the permeability of seabed soil and the depth of the tunnel have a small effect on the internal stress of the tunnel,whereas it has a great effect on the pore water pressure of the seabed soil;④the incident angle of the seismic wave has a great influence on the internal stress of the tunnel and the pore water pressure of the seabed soil.