Research on the influence zone dividing of tunneling adjacent to existing tunnel based on ultimate strain criterion

This thesis estimates the effects of tunneling parallel to or crossing the existing tunnel. According to the ultimate strain criterion, this paper suggests effective method to simulate failure process of geological materials, which combines with strength reduction FEM. Through numerical simulation and criterion of the influence zone dividing, the regulation of the stability of an individual tunnel was proposed in this paper, moreover, dividing influence zones by using upper and lower limit if surrounding rock parameters, which was defined as the strong influence zone, the weak influence zone, and the non-influence zone. Furthermore, this thesis discusses the transverse and longitudinal effect of two orthogonal excavation. Conclusions that were drawn in this paper can be utilized in actual excavation.