Numerical Simulation Of The Site Effect Of Earthquake Ground Motion

The local site condition is an important factor affecting the ground motion response,and it has a great influence on the seismic wave field transmission and the ground motion energy.Typical local site conditions,such as layered site and fault fracture site,have always been a hot research topic.Based on numerical simulation method,the characteristics of ground motion response of these two kind of site models are studied.,the main contents as follows:(1)Learning and summarizing the predecessors’ research theories,results and methods in the site effect of ground motion,laid the research idea of this paper.(2)Learning and summarizing the basic theory of seismic wave and the method of using ABAQUS finite element numerical simulation software for studying the site effect of ground motion.(3)The study of semi-infinite homogeneous site simulation.Based on the full wave field numerical simulation,the propagation characteristics of seismic wave field and amplitude of ground motion are studied under the condition of Rayleigh wave incident.(4)The study of the local layered site simulation.Based on the full wave field numerical simulation,the propagation characteristics of seismic wave field and the amplitude of ground motion energy are studied under the condition of Rayleigh wave and SH wave incident.(5)The study of fault fracture site.Based on the full wave field numerical simulation,the propagation characteristics of seismic wave field and the amplitude of ground motion energy are studied under the condition of Rayleigh wave and SH wave incident.Through the research above-mentioned,the main conclusions are obtained as follows:(1)The soft soil overburden layer of the site has amplification effect on ground motion.The wave field conversion and coherent interaction on the interface of the layered soil layer of the site lead to the amplification effect of the ground motion.When the thickness of the overburden soil is large,the amplification effect of the ground motion decreases.In the boundary area between hard rock and overburden soil,the seismic energy in this area is larger than that in the overburden area because of the accumulation of seismic waves.(2)The fault fracture zone in the fault fracture zone has amplification and isolation effect on ground motion.When the seismic wave propagates to the fault fracture zone,it will reflect and refraction between the low-speed fault zone and the surrounding rock high-speed zone,and the wave field conversion and coherence will form the trapped wave.The fault fracture zone has the effect of magnifying the ground motion energy,but it has the isolationeffect on the side that deviates from the source,and its strength is related to the shear wave velocity and the width of the fault fracture zone.