A Study On The Stress Concentration Law And Its Correlation With Geological Hazards In The Northwest Sichuan

Located in the eastern margin of Qinghai Tibet Plateau,Northwest Sichuan Basin is formed by the collision of the India plate and the Eurasian plate,and the high mountain gorge region in the transitional zone between the Northwest Sichuan Plateau and the Sichuan basin.Tectonic system in the region is very complex and unique,modern tectonic movement is intense,active faults,forming a large range of the high stress concentration zone,strong earthquake activity is frequent,and cause serious geological disasters of collapse,landslide and debris flow,but also to the entire region's people's life and property caused heavy losses.In this paper,based on the study of the development of regional large deposits and its environmental effects,we can grasp the regional geological conditions of the study area and analyze the engineering geological conditions of the study area.The geological background of the study area is constructed as a whole,and the whole research framework is formed.Through the study of regional geology,geological structure and previous research results,combined with the measured stress data,GPS displacement data,establish the finite element simulation model of geological structure,Northwest Sichuan inversion of stress field and its change trend,analysis of tectonic stress field characteristics and high concentration.Through the investigation of geological disasters in the field and the detailed remote sensing interpretation of the key sections,the characteristics and distribution of the geological disasters of the large-scale landslides in the study area are summarized and analyzed.Finally,through the comprehensive large-scale geological hazards development law and stress field numerical simulation results,the distribution map of geological hazards and high stress concentration region fitting analysis,evaluation of high stress and landslide disaster association.The main conclusions are as follows:(1)In the northwest of Sichuan is located in China's famous "North-South Seismic Belt in the middle of North Central,located in the eastern part of the India plate and Eurasian plate collision together to form the edge of the Tibetan Plateau area,across the Northwest Sichuan Plateau and the Sichuan basin and its transition zone alpine valley region.Constitute the area from west to east gradually converge lying on the word "A" type tectonic system and internal fault block of North-South Minshan uplift fault zone of the Minjiang River and Huya fault zone from the south east boundary of the south margin fault combination Longmen North East and North West boundary fault fold belt of Qinling Mountains EW tectonic belt,control the strong crustal movement.(2)High stress area in the northwest of Sichuan is mainly distributed in the construction of intensive distribution,fault zone and deep valleys,uplifting River confluence and rapid new strong tectonic activity area,can be divided into high stress zone,such as Minshan high stress area,Longmen Mountain high stress area,Maerkang high stress area,and Xianshui river high stress area,and Qinling tectonic belt high stress area.(3)According to the new tectonic features and tectonic conditions in different regions,summarizes 4 kinds of Northwest Sichuan highland stress concentration mode: the "bottleneck" of high stress concentration;the "diagonal intersection " high stress concentration;the three groups of faults at the intersection of stress concentration;the trapezoidal block end of the Highlands stress concentration.(4)In the northwest of Sichuan Province,there are more and more large-scale and more landslide disasters in the northwest of Sichuan Province,of which there are more than 504 large landslides,and the other is the super large landslide,with a total of more than 418.The White River in Longjiang in 259,the Fujiang River Basin 187,Minjiang River Basin 161,Heishui River 45,Zagunao River Basin in 50,155 in the Dadu River,Tuojiang River Basin 49.The total amount reached(5)Landslide in Northwest Sichuan occurs and micro topography has a close relationship,they usually occur in the following categories have obvious amplification effect on seismic wave topography: slope parts of Valley shoulder slope wide Canyon-transition from slow to steep;the thin mountain ridge area;the isolated hill hill position or multiple free surfaces;the concave parts of the river.(6)According to the Northwest Sichuan high stress zone and the field investigation and remote sensing interpretation of Northwest Sichuan large landslide distribution,it can be concluded that the Northwest Sichuan high stress area developed large-scale landslides in 600,the high stress area at 146 min,the middle section of Longmen mountain high stress area in 220,Barkam high stress area 12,fresh water river high stress area 34.Qinling Mountains tectonic belt high stress area 188 place.(7)The Northwest Sichuan highland stress distribution and the distribution of large-scale landslides based on high stress area should be from the epicenter of historical earthquake and landslide disasters,coupled with the valley(potential source region)and geological disasters and high stress soft rock strong deformation zone of slope and landslide,high slope area the surface strong denudation and landslide,high concentration of stress concentration zone of active faults directly form the boundary of landslide and high stress concentration area of new horizontal extrusion weakening the binding force between layers and landslide etc.the relationship between the two aspects of research.