Numerical evaluation of the effects of ground reinforcement method in double-deck tunnel junction

摘要

In this paper, 3D analysis was performed to consider thecharacteristics of multi-axial direction reinforcement usingloop-type wire and the variation of pillar width betweenmain tunnel and branch tunnel. The values of reinforcementdetermined from the existing and developed methods werecompared to each other by numerical simulation. Accordingto the results, the following conclusions can be drawn.1. Reinforcement effect of loop-type method wasbetter than its existing method for all rock grades.2. 3-D loop-type reinforcement method considerablyincreased the safety factor.3. In less than 0.2D rock pillar width, regardless ofthe conditions, strength/stress ratio was about 1.0,it was shown unstable.4. It was shown that since more than 0.2D showing atendency to increase the strength/stress ratio, and3-grade rock of strength/stress ratio increasedsignificantly than 4-grade.5. Deformation of pillar occurred in the direction ofthe main tunnel due to difference of tunnelsections.