ABAQUS numerical simulation study on the effect of high stress relief groove depth on the pressure relief of tunnel peripheral rock
In order to investigate the pressure relief effect of tunnel excavation and its parameter optimization under a high stress environment,this paper comprehensively analyzes the pressure relief effect under different depth conditions of the pressure-relief groove in tunnel rock excavation with the help of discrete element numerical simulation software ABAQUS.The results show that when the excavation depth of the pressure-relief groove is shallow(≤5% of the tunnel width),it has limited influence on the stress distribution of the tunnel surrounding rock,the displacement near the slotting point is small,and the rock body at the bottom corner of the tunnel on the slotting side shows elastic characteristics.The plastic change is not apparent,the bottom plate and slotting point displacement change are small,but the displacement of arch waist,elevation arch and arch top increases with the increase of slotting depth,which at this time leads to the increase of local stress,especially obvious in the area near the slotting point,the stress level in this area is elevated by about 13.29%,which is unfavorable to the stability of the two tunnel gangs.As the depth of the unloading slot increases,the stress concentration area migrates to the end of the slot and shrinks.The elastic state gradually transitions to plastic,leading to permanent deformation.When the unloading slot is excavated to 15% of the tunnel width,the stress concentration area is close to the limit,and the stress unloading amplitude is close to the maximum(unloading stress drop of 97% ).The increase in displacement is still rising,and the bottom part of the unloading slot is where the elastic energy accumulates,affecting the tunnel's stability.The increase in lateral pressure coefficient leads to an increase in stress distribution.The increase in lateral pressure coefficient leads to uneven stress distribution and stress concentration,which seriously affects the stability of the structure.The magnitude of displacement change and elastic energy change are significantly larger at a lateral pressure coefficient of 2.0 than at a lateral pressure coefficient of 1.0.
pressure-relief grooveslotting in the roadway wallpressure-relief mechanismdeep tunnel
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