Research Of The Finite Element Mesh About The Underground Media Of Three-dimentional Horizontal Layer

With the continuous development of China’s civil engineering and technology,the finite element software has been more and more widely used. Finite elementanalysis software can be drawn to meet the engineering precision approximation andalter analysis of the actual structure, and it also can solve many complex problems inpractical engineering, which can not be solved in theoretical analysis. Especially, theearthquake is an unavoidable natural phenomenon, which has caused great harm topeople’s lives and property in recent years, and the use of finite element software cananalyze the complex force of the building in the earthquake, playing a role inpreventing the earthquake and reducing the disaster. At present, there are a lot ofresearches on the application of finite element software to analyze the single buildingor the interaction between two buildings in the earthquake, but less to analyze themutual influence between multiple buildings in an area earthquake. The purpose ofthis paper is to research mutual influence in an area of multiple buildings underseismic action, and the finite element mesh of large area three-dimensional layeredsubsurface by general finite element software. Under the premise of ensuring theaccuracy, the finite element calculation can less occupy resources and time, and getthe best efficiency program. The following work is completed in this thesis:(1)Through summarizing a large number of relevant literature, we analyse thereare limitations and problems to carry out finite element analysis of horizontal layeredsite seismic response at home and abroad. Besides, we induce the methods ofresearching horizontal layered site seismic response, and put forward the methods ofanalysis and the ideas of basic framework for the horizontal layered site under theaction of earthquake.(2)The numerical method of seismic horizontal layered site, the constitutivemodel of soil unit in ABAQUS finite element software program unit, the layeredapproach of the horizontal layered soil has been researched, and the ABAQUS finiteelement modeling of soil has been verified in this thesis. According to the proportionof different sizes and types of finite element mesh, the efficiency issue of the modelto obtain accurate values in the static calculation is discussed. So the reasonablemethod of contacting different soil bodies is acquired, which is prepared for furthercomputational analysis.(3)Basing on the use of infinite element method of one-dimensional and two-dimensional soil in ABAQUS finite element analysis, we extend to threedimensional infinite element, simulating the semi-infinite soil. At the same time, weexplore the seismic response simulation method of three-dimensional layeredsubsurface, and contrast fixed boundary conditions of the finite element and themeshing method of different models, determining the relationship of accuracy andefficiency. And then we contrast the amplification factor of the existing site seismicwave reaction, illustrating that the method of three-dimensional soil dynamicresponse analysis is feasible and reasonable in the ABAQUS software.(4)We adopt different seismic intensity and the different input depth of seismicwave to study the dynamic response of the model, and summarize the regularityresults, and contrasted the existing research conclusion, proving the applicability ofthe proposed model. Comparative analysis includes seismic response accelerationamplitude of surface and underground observation point, acceleration time historycurve, amplification factor.