Numerical Analysis of Deformation Influence of Horizontal Adit Construction on Main Tunnel Intersection Structure

The 3D finite element simulation are adopted to study the surrounding rock deformation regularity of main tunnel during the horizontal adit construction stage. The Zhongtiaoshan highway tunnel is taken as an example. The research results are shown as follows: Horizontal adit excavation destroys the original arching effect of the main tunnel, which leads to stress concentration at the intersection of primary supporting structure. The first excavation step plays an important play in the surrounding rock deformation of the intersection. The influence range of the main tunnel which due to the horizontal adit excavation is 1.2D.