Research On The Mechanism Of High Deformation And Rupture Due To Active Fault

ABSTRACT:With the movement of urbanization driven by the rapid development of economy, the scale of urban area is expanding and the population is becoming increasingly extensive. The impact of active faults underground near the urban area becomes extremely necessary. Recent economic development promotes the development of modern science and technology. It makes the detection technology for active fault detection in city get great progress. Meanwhile, based on the research of underground structural model and construction of seismic source, study on perniciousness of active faults underground near the urban area also tends to be mature.After analyzing the methods which is used in study of the impact of active faults underground near the urban area, such as, theoretical analysis, numerical simulation, experimental study, survey in the site, there presents a new method to integrate theoretical analysis and numerical simulation in the article to replace the thinking of making the rock and soil mass as a whole for calculation. We introduced the infinite element boundary conditions and separate the rock stratum from soil layer, then receive the displacement on the surface of the rock stratum by method of Okada and get the displacement on the surface of soil by FEA. In the course of the three-dimensional modeling, we build the model of geology in GOCAD through the ideology from BIM, and then import it to Abaqus by its Secondary development platform.By the new approach, we systematically carried out mechanism for typical soil layers overlying role in different fault when the basic failure process and research on the corresponding phenomenon. We analysis the differences in displacement of the ground surface on different thickness of overburden, angles of active tectonic, amount of faulted dislocation, and dislocated forms. It shows us that the displacement on surface will get smaller if the overburden become thicker when the other factors keep same. The displacement will increase with the amount of faulted dislocation. When the angle of active tectonic get bigger, the peak of the surface displacement will be greater and the influenced area will become more concentrated. Among different forms of active fault, the displacement and the slope of the displacement curve on the surface of upper plate of the thrust faults is the biggest. So we can get that thrust faults have the biggest influence on the overlying soil on its upper plate.Meanwhile, we combined with "The Urban Active Fault Detection and Seismic Risk Evaluation" project, and establish three-dimensional active fault model of the target cities,and use the static FEM to analysis the numerical simulation, and predict the surface rapture zone and strong deformation zone caused by active fault under urban areas. Through the study of this project, we provide fundamental basis for the seismic fortification and disaster prevention and mitigation of urban areas, and also provide a reference for similar scientific research in the future.