Simulation Method of Tunnel Excavation under Plane Strain Condition

For a different supporting time hole into subway tunnel excavation, with the initial stress in the surrounding rock in the tunnel and initial stress reverse impose the same release the equivalent of the simulation node, consider themselves lining load conditions in a hole under the formation of linear elastic numerical solution. The analysis indicated that with the increasing of the stress release rate, the hole arch displacement gradually decrease. When the stress release rate is bigger than a value, the hole arch displacement is increase rapidly, this is a marginal value (the biggest permission release rate); Under the identical hole diameter condition, the burying depth is bigger, the biggest permission release rate is bigger; Under the identical burying depth condition, the hole diameter is bigger, the biggest permission release rate is smaller.