考虑渗流影响与中间主应力效应的深埋圆形盾构隧道弹塑性统一解OA

[Objective]The influences of seepage and stress fields on the deformation of the surrounding rock and the structural stress of shield tunnels are significant under water-rich geological conditions.[Methods]Based on seepage field theory and elastoplastic mechanics,combined with the unified strength theory and the non-associated flow rule,this study derived an elastoplastic unified solution for circular shield tunnels considering seepage effects and the intermediate principal stress effect.The characteristic curve method was employed to analyze the stability between the surrounding rock and the lining structure.After verifying the accuracy of the proposed mechanical model,this study further investigated the influence patterns of far-field steady seepage pressure,permeability coefficients of the surrounding rock and lining,intermediate principal stress,initial geostress,and support reaction on the plastic zone radius and radial displacement of the tunnel wall.[Results]The results indicated that:the existence of a seepage field expanded the plastic zone range of the surrounding rock and increased the radial displacement of the tunnel wall;the plastic zone radius and the radial displacement approximately increased linearly with increasing far-field steady seepage pressure,decreased nonlinearly with increasing permeability coefficient of the surrounding rock and support reaction,increased nonlinearly in an approximately exponential manner with increasing lining permeability coefficient and initial geostress,and decreased nonlinearly in an approximately exponential manner with increasing unified strength theory parameter b.[Conclusion]These findings provide references for tunnel construction and structural design in water-rich regions.