Numerical Simulation Research On The Prediction Of Rock Burst Under High In-Situ Stress In The Deep-Buried Overlong Tunnel

In recent years, with the constant increase of the underground projects in greater depth, the high stress caused a growing number of engineering disasters. Because the rock burst has the characteristics of abruptness and hysteretic nature, so the rock burst prediction and prevention have become the key technical problems of the underground engineering design and construction. Therefore, in order to put forward the applicable reliable prediction and prevention methods, it is necessary to further research on rock burst according to the different characteristics of the projects, it is very important for the design and construction of underground engineering.This paper takes Qinling Mountains tunnel of Hanjiang River to Weihe River diversion project as the research object. The characteristics of this project is buried depth, high ground stress and complicated geological conditions. According to these characteristics, this paper conducts the research on rock burst prediction and prevention in deep-buried overlong tunnel under the condition of high in-situ stress. Chief work and conclusions are summarized as the following:(1)Collect and sort out the literature and data of domestic and overseas related to rock burst. To comprehensive analysis the rock burst prediction and prevention technology under the high in-situ stress when excavation the tunnel. Summarized the research status about the criterion of high stress and rock burst. Summarized the research status about the numerical simulation and the mechanism of rock burst.(2)To collect the geological data of Qinling Mountains tunnel. Investigation and analysis of the regional topography, formation lithology and geological structure etc. Identify the tectonic stress is the dominant stress, rock hard and brittle. These are the basic conditions of rock burst.(3)On the basis of engineering mechanics properties of tunnel surrounding rock and in-situ stress inversion data., By discrete element method software(3DEC), simulation of initial and secondary stresses of Underground Excavation in seven representative depth section of the study area. Analysis of secondary stresses, displacement and damage. Choose five different types of rock burst criterion to predict the rock burst proneness, and compare the comprehensive evaluation results and the actual situation.(4) Study on the shotcrete-bolt support numerical simulation in tunnel which happened light and medium rock burst. Pointed out that the shotcrete-bolt support can not completely prevent the occurrence of rock burst, but can effectively reduce the damage degree of tunnel rock burst disaster.