Study On The Characteristics Of Deformation And Disaster Caused By Rock Mass For Large Scale

The natural disasters caused by crustal movement have brought great losses to the country and human beings.Meanwhile,the crustal movement has attracted the attention of scholars at home and abroad.The crustal movement has caused the change of stress field,which is the key factor to evaluate the regional crustal stability.The Sichuan Basin and its surrounding areas have always been a very important active tectonic belt,and are the most intense and typical areas of neotectonic movement in China.It is of great value to study the tectonic stress field and the regional crustal stability in this area.Based on the relevant theories of active structure and fault zone movement,this paper combines the characteristics of tectonic unit,regional structure and stratigraphic lithology of Sichuan Basin and Longmenshan fault zone from the macroscopic view of giant scale.The structural stress field of Sichuan basin and Longmenshan fault zone is simulated numerically.The simulation work is carried out on the FLAC3 D platform of finite difference analysis software.The numerical model is based on the stratigraphic analysis and crustal structure of the Sichuan Basin and the eastern margin of the Qinghai-Tibet Plateau,and the relevant lithologic data(Youngundefineds modulus,Poissonundefineds ratio)are used.Rock mass density)sets up the geological model by assigning the geometric model into blocks,and determines the corresponding exact boundary conditions by using GPS motion displacement velocity and adjusting load parameters.The simulation results show that the maximum principal stress concentration zone is mainly located at the end of the fault,the local inflection point,the intersection of Longmenshan fault and Xianshuihe fault,the Longjipa fault and East Kunlun fault,the Huaying mountain fault,and the Longmen fault zone.The stress concentration near Huayingshan fault zone,Longjipa fault zone and Xianshuihe fault zone is obvious.The macro-regional distribution characteristics of debris flow,landslide and dangerous rock collapse are mainly controlled by the regional tectonic system.Large and medium-sized debris flows and landslides are concentrated in the combined parts of different structural systems,where the structural systems make sharp arcs,where the tectonic systems intersect with each other,or where the tectonic systems intersect with each other.Both sides of deep fault and strong active area of neotectonic movement such as earthquake.Based on the numerical simulation results,reasonable suggestions and effective references are given for engineering construction activities near the main fault zones in Sichuan Basin and Longmenshan area.