Abstract: To reveal the interaction mechanism of twin tunnel tubes under dynamic excavation conditions, the Shat? antou Tunnel of the National Highway 351 reconstruction project is taken as the engineering background. The study investigates the stress distribution, deformation, and evolution of the plastic zone of the surrounding rock, as well as the loading and failure characteristics of the middle rock pillar and the internal force distribution of the support structure under dynamic excavation conditions for seven groups of different clear distances in deeply buried tunnels.The interaction mechanism of first and subsequently excavated tunnel tubes under different clear distance conditions for deeply buried tunnels with small clear distance is analyzed. The results show that during single tunnel tube excavation, stress concentration areas form in the lateral sides and the front of the tunnel face, with the maximum stress located at the arch corner, and significant settlement at the arch crown and deformation at the arch bottom. Under dynamic excavation conditions, the stress concentration at the middle rock pillar and the side in front of the sub? sequently excavated tunnel tube face near the first excavated tunnel tube is higher, peaking at a clear distance of 0.3D. When the clear distance exceeds 0.5D, a stable bearing core can form inside the middle rock pillar. Under small clear distance conditions, the internal forces in the lining of the first excavated tunnel tube are significantly affected by the excavation of the subsequent tunnel tube. At a clear distance of 0.3D, the axial force of the initial support in the first excavated tunnel tube reaches its peak at the arch waist, while the bending moment of the support peaks at the arch foot.