Analysis of plastic zone boundary of circular tunnel under the asymmetric load

摘要

In order to study the stress distribution features of the surrounding rocks a long the circle tunnel after the roadway excavated and the radius size of there leased circle, first analysis of the stress distribution characteristics of the surrounding rock, on this basis, circular tunnel for the elastic and plastic zone is derived based on the mohr coulomb strength criterion. The plastic zone in the surrounding rock of the tunnel under the conditions of different side pressure, different stress, different cohesion and different friction angle was obtained with the theoretical calculation. The evolution of the plastic zone is summed up from plastic zone equation. The lateral pressure coefficient has a great influence on plastic radius; with the increase of stress, the plastic zone increases; with the cohesion increases the plastic zone reduced; with the cohesion increases the plastic zone reduced.