关键词: 铁路隧道, TBM, 围岩扰动, 应力重分布, 弹性应变能, 力流, 岩爆, 数值模拟

Abstract:  A deepburied railway tunnel using a tunnel boring machine (TBM) is subjected to a high level of insitu stress, and the stress field is complex and variable. Hence, to study the surroundingrock disturbances caused by TBM excavation of deepburied railway tunnels and investigate its stressredistribution characteristics and the stressredistribution mechanism, a TBM tunnelexcavation model is established using numerical simulation software FLAC 3D. The stressredistribution characteristics during the TBM tunnelexcavation process are analyzed according to the forceflow theory, and positions that are prone to rockburst are predicted based on the elasticstrainenergy theory. The research results show the following. (1) The surroundingrock stress and elasticstrain energy of the TBM tunnel are approximately symmetrically distributed up and down, and the TBM deadweight slightly affects the stress distribution of the surrounding rock. (2) In the horizontal tectonicstress field, the redistribution of the transverse stress obviously affects the stress concentration of the maximum principal stress, and the phenomena of maximum principalstress concentration at the crown and arch bottom, arch shoulder and arch feet, and arch waist are mainly caused by the stress concentration of the transverse, shear, and vertical stresses. The stressconcentration degree of the maximum principal stress reflects the jump level of the elasticstrain energy. Rockbursts have the greatest possibility of occurring at the arch bottom and crown of the TBM tunnel.

Key words: railway tunnel, TBM, surrounding rock disterbance, stress redistribution, elasticstrain energy, force flow, rockburst, numerical simulation