Numerical Study On The Tectonic Stress Field Of The Chuan-dian Rhombic Block

The Chuan-Dian rhombic block is located in the south-east of the Tibetan Plateau. TheTibetan Plateau is situated on the south-west of China, includes some areas in Sichuan,Yunnan and Tibet. The Chuan-Dian rhombic block is the most significant earthquake activityarea in China, the tectonic activity of this area is so complicated that the neotectonicdeformation and seismic activity of this area are very intense. It is the following reason thatcontribution to this phenomenon. Firstly, the crustal material in Tibetan Plateau is movingfrom west to east since the Cenozoic era. Secondly, the Assam vertex keeps wedging.So, it isof immediate significance to study on the tectonic stress field of the Chuan-Dian rhombicblock and the numerical simulation of the hazard effects. It also can provide evidence for theresearch in the dynamic mechanism and the seismic hazard effects of the active fault insouth-west of China. Besides, under the similar condition, people can take the result of thispaper as an example to analyze the seismic activity and plot out the projects.This paper researched on the characteristics of the contemporary tectonic stress field ofthe south-west part and the whole mainland of China, and summarized the feature of theactive fault in this area. On the basic of the research results, this paper collected andstatistically analyzed the real ground stress of the Chuan-Dian rhombic block and re-dividedthe block in the Chuan-Dian area. Applying the Midas\GTS NX, the finite element analysissoftware, this paper established numerical model, fitted the GPS displacement of tectonicdisplacement field and inversed the feature of displacement field, principal stress field andshear stress field of the Chuan-Dian rhombic block.The main conclusions of this paper are as follows:(1)The displacement of the Chuan-Dian rhombic block shows a tendency of rotating, theboundaries of the block are strike slip faults.(2) The stress and displacement of the tectonic stress field is concentrated: generallyspeaking, the stress of the tectonic stress field focus on the intersection of different faults, thecrotch of the same echelon fracture and the strong squeezing zone of the block; thedisplacement of the tectonic stress field are concentrated on fault zone.(3) Applying the intersection of the major and minor principal stress and the fracture, under the condition of plane strain, this paper analyzed the mechanical properties of thefracture from the structural mechanical view of point. The result of the simulation isconsistent with the geological data which means this article has both theoretical and practicalimplication.