Numerical Study On The Tectonic Stress Field Of Longmenshan Fault Zone And Assessment Of The Regional Crustal Stability

Active structure has been the hot point of research for several years because ofthe significant impact of earthquakes and other natural disasters on human activities.Regional tectonic activity has close relationship with variation of the stress fieldwhich is the key factor in the evaluation of regional crustal stability. TheLongmenshan fault zone is an important active tectonic zone of the eastern edge ofthe Tibetan Plateau which is the most intense and typical regional among Chineseterritory neotectonism. It has important significance to carry out research on tectonicstress field and study the Longmenshan regional crustal stability in this area.The article is based on active tectonic theory and combines with the tectonicunits of Longmenshan fault zone, regional structural features, and geomorphologycharacteristics, strata law magmatic evolution et. Simulating for Longmenshan faultzone tectonic stress field and finishing the simulation solver working on the finiteelement analysis software ANSYS platform. Simulation models takes full advantageof the measured seismic profiles, the chromatographic profile and Precision Strip landtopography DEM terrain data and other information eastern edge of the TibetanPlateau predecessors had done and established the geometry of depth and shallow inLongmenshan fault zone. The model of the finite element numerical simulation isbuilt by assign the rock mechanics data (Young’s modulus, Poisson’s ratio andmaterial density) to these clumps in geometry model; the effect crowding out tosoutheast in Qinghai-Tibet Plateau is simulated by using correspondence betweenshallow and deep crust stress values to get the deep boundary stress values and carryout stress loading.The simulating result shows that the active characteristics of Longmenshan FaultZone, the distribution of regional stress field and regional rising and deformation haveclose relationship with the tectonic units, the characteristics of regional structure,regional hard complex rocks. Regional structural characteristics determine theproperties that the major fault zones were suffered by extrusion and deformation for the long time, and the eastern edge of the Longmenshan fault zone and its differencesin the mechanical properties of the base space resulted in a significant difference inthe deformation between the Longmenshan fault and the front basin. The stress-straindifferences between eastern and western highlands led to the emergence of thestrongest gradient zone; the simulation results also explained some other importantgeological problems of the Longmenshan fault zone. According to the simulationresults, discussing the crustal stability of the Longmenshan area and putting forwardsome advice and effective references for engineering activities in the Longmenshanarea.