Analysis Of Tsunami Effect On Structure And Engineering Prevention And Control Methods

Tsunami is one of the serious natural disasters in coastal areas,which is mainly caused by severe submarine mass movement up and down causing disturbance of bulk water above the seabed.The tsunami wave is a three dimensional wave phenomenon,the forefront of the tsunami wave has extremely strong turbulent intensity,vorticity,and impact force.It generates tremendous impact effect on the coastal structures,which is the direct reason of the damage and destruction of the structures.Based on the computational fluid dynamic theory,the volume of fluid(VOF)method is applied to capture the free surface motion of the tsunami waves,the RNG k-? model is used to describe the energy dissipation mechanism in the tsunami bore,a three dimensional wave numerical model of an experiment of dam-break tsunami bore impact on a structure is developed in this paper,and also the effectiveness of the numerical model was validated.Based on the numerical model,the factors to influence the individual structural member under the impact of the tsunami waves are discussed.The impact force generated from the tsunami wave on structure was controlled by the upstream cross section width of structural member,with the increase of upstream cross section width of structural member,the impact force increases linearly,while the change of cross section along the flow direction length has little effect on the impact force.Therefore,it is be appropriate to increase the cross section length along the flow direction to enhance the lateral stiffness of the structure but the tsunami waves force acting on the structure is not increase in design of the structure anti tsunami.The three dimensional numerical model of the tsunami wave impingement acting on a four storeys reinforced concrete frame structure is set up with FLOW-3D software to simulate the impact force of the tsunami wave acting on the structure and their interaction process.The time history curves of horizontal impact force on the structure due to the tsunami wave were obtained through the numerical simulation.It is shown that the impact force on the structure increases with the tsunami wave height increasing.Nonlinear static analysis of the frame structure under the impact of the tsumani wave is carried out by ANSYS,the results show that the frame structure presentation shearbending deformation,and with the increase of tsunami wave height,the structural deformation increases.Based on ANSYS software,the finite element model of frame structure modal analysis is established to obtain the basic eight-order natural frequencies and mode shapes of the structure.The transient dynamic response analysis of the structure under impact of the tsunami wave is carried out and the magnification coefficient of the tsunami wave on the structure is confirmed to be 1.2,which could provide a reference for the design of anti-tsunami buildings.The three dimensional numerical model of the tsunami wave impact on a coastal building is established to analyze the influencing factors of the impact force acting on the building by the tsunami wave.It is shown from the analysis that the upstream wall opening rate increase,foundation of ascension and set sea wall reduce the impact force.Tsunami-resistant design calculation example analysis of the reinforced concrete frame structure with different layers is carried out,and the engineering prevention and control methods on tsunami disaster are also presented.