Classification Of Research Area Stress And Surrounding Rock Deformation Prediction Of Highway Tunnel

With the large-scale construction of infrastructure in the western development of China,more and more deep buried roads,railway tunnels and underground tunnels of hydropower and mines will be built or are being built under high ground stress environment.The prediction and prevention of large deformation of surrounding rock has become one of the key technical problems in underground engineering.Therefore,in order to provide reliable and applicable discrimination basis and prediction method,it is necessary to further study the large deformation of tunnels with different engineering characteristics.This paper takes a tunnel project as the research object,aiming at the characteristics of large buried depth,high ground stress and complex geological conditions,carries out the numerical simulation and prediction research on the large deformation of rock burst of ultra long deep buried tunnel under the condition of high ground stress.The main work and conclusions are as follows:(1)According to the in-situ stress test and analysis of hydraulic fracturing in drilling site,the maximum horizontal principal stress value in the tunnel area is obtained;based on Hoek Brown strength theory,the new high geostress evaluation method and standard method are used to comprehensively evaluate the in-situ stress in the tunnel area,and it is concluded that YK58+595-YK58+840 section belongs to high geostress state(2)Based on fuzzy comprehensive evaluation method and extension theory,the large deformation of surrounding rock is predicted.Select the main factors that affect the large deformation of surrounding rock,respectively establish the evaluation index system and classification standard,determine the weight of the factors,classify the large deformation of surrounding rock,and divide the tunnel area into slight large deformation,medium large deformation and serious large deformation.The comparative analysis shows that the calculation results of the two evaluation methods are basically consistent,and the surrounding rock of YK58+595-YK58+840 section belongs to serious large deformation.(3)FLAC finite element software is used to establish a two-dimensional geomechanical model.The deformation characteristics of surrounding rock after tunnel excavation are simulated and analyzed.The maximum deformation and corresponding parts of surrounding rock in 7 sections of tunnel engineering are obtained.The numerical simulation shows that the surrounding rock of yk58+595-yk58+840 may have serious large deformation,which is also the high geostress section.