It is of great significance to determine the stability of surrounding rock for the excavation of shallow broken surrounding rock tunnel.Based on Xiaolangdi North Bank Irrigation Area project,3DEC discrete element software was used to simulate tunnel excavation process of jointed broken rock mass and calculate the displacement and stress state of tunnel arch block.The chain reaction of tunnel collapse caused by the instability of key block was studied.The influence of block joint strength on the stability of surrounding rock was analyzed.Finally,the influence of advance support meas-ures on the overall stability of tunnel was simulated.The results show that the arch block is obviously unstable during ex-cavation,which leads to the whole surrounding rock collapse,and the sequence of block instability is analyzed.Increasing the strength of joint surface of surrounding rock can significantly improve the self-stability of surrounding rock.After adding surrounding rock support measures,the maximum ground subsidence displacement is 0.9 cm,which is close to the field monitoring result.
关键词
浅埋隧洞/离散单元法/节理岩体/围岩稳定
Key words
shallow buried tunnel/discrete element method/jointed rock/surrounding rock stability
维普
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