Analysis of Influencing Factors of Rockburst Tendency of Deep Buried TBM Tunnel with High Ground Stress
Research purposes:Rockburst disasters are most prominent in the construction of deep-buried high-ground stress hard rock tunnels,and the clear influence of the main factors affecting the occurrence of rockbursts is of great significance for the prediction and prevention of rockburst disasters.This paper takes a new mountain TBM tunnel in southwest China as the engineering background,based on the summary analysis of the conditions of rock explosion,based on the FLAC3D software to establish a numerical model of the TBM tunnel boring,analyze the impact of the ground stress and the strength of the surrounding rock on the propensity to rock explosion;and then use the game combination of empowerment-gray correlation analysis to determine the degree of influence of different factors on the propensity to rock eruption.Research conclusions:(1)High energy storage brittle rock mass,sufficient energy source,and engineering excavation unloading are the conditions for the occurrence of tunnel rockburst.(2)Rockburst propensity increases gradually with the increase in depth of burial.Lateral pressure coefficient＜1.0,the side wall of the largest rock explosion tendency;lateral pressure coefficient＞1.0,the arch(arch bottom)at the largest rock explosion tendency.With the increase in lateral pressure coefficient,the arch and arch shoulder rock explosion propensity gradually increased,and the side wall rock explosion propensity gradually decreased.(3)The rockburst tendency increases slightly with an increase in cohesion.When the internal friction angle is small,the rockburst tendency increases with the increase of the internal friction angle,but the larger the internal friction angle,the smaller the influence on the rockburst tendency.(4)The degree of influence of different factors on the rockburst propensity is burial depth＞internal friction angle＞lateral pressure coefficient＞cohesion.(5)The results of this study can provide support for the determination of influencing factors of rockburst prediction in high-ground stress tunnels and also provide a reference for the prevention and control of rockburst disasters.
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