TBM深埋铁路隧道地应力水平高，应力场复杂多变。为研究TBM开挖深埋铁路隧道引起的围岩扰动，明确其应力重分布特征及产生机制，依托实际铁路隧道工程，采用FLAC 3D数值模拟软件，建立TBM隧道施工掘进模型，基于力流理论对TBM隧道开挖过程中的围岩应力分布特征及弹性应变能进行分析，采用弹性应变能大小为指标对隧道岩爆位置进行预测。研究结果表明： 1)隧道围岩应力及弹性应变能大致呈上下对称分布，TBM的质量对围岩应力分布影响不大； 2)在水平构造型应力场中，σx（横向应力）的重分布对σ1（最大主应力）的应力集中程度影响显著，拱顶和拱底、拱肩和拱脚、拱腰处最大主应力集中分别主要由横向应力、剪应力、竖向应力集中引起； 3)σ1的应力集中程度反映了弹性应变能的跃升水平，隧道拱底和拱顶发生岩爆的可能性最大。
A deepburied
railway tunnel using a tunnel boring machine (TBM) is subjected to a high level
of insitu stress, and the stress field is complex and
variable. Hence, to study the surroundingrock
disturbances caused by TBM excavation of deepburied
railway tunnels and investigate its stressredistribution
characteristics and the stressredistribution
mechanism, a TBM tunnelexcavation model is established
using numerical simulation software FLAC 3D. The stressredistribution characteristics during the TBM tunnelexcavation process are analyzed according to the forceflow theory, and positions that are prone to rockburst are predicted
based on the elasticstrainenergy
theory. The research results show the following. (1) The surroundingrock stress and elasticstrain 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 tectonicstress field, the
redistribution of the transverse stress obviously affects the stress
concentration of the maximum principal stress, and the phenomena of maximum
principalstress 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
stressconcentration degree of the maximum principal
stress reflects the jump level of the elasticstrain
energy. Rockbursts have the greatest possibility of occurring at the arch
bottom and crown of the TBM tunnel.
