Analysis on Mechanics of Intersection of Adit and Main Tunnel

Nowadays with the development of the national economices of our country,the needs for infrastructures,especially for traffic infrastructures such as railways and highways are continually increasing,which leads to tremendous growth of the number of long mountain tunnel projects.The adits connecting two long tunnels are recognised as the essential auxiliary structures to facilitate refuge rescue,maintenance and management during traffic operation.Through 3D FEM numerical simulation analysis of construction of the adit and main tunnel intersection structure with different intersection angles,this paper draws the conclusions that the smaller the intersection angle,the higher the concentration degree of the surrounding rock stresses and the larger the adit lining stresses.Therefore,special design is necessary to strengthen the adit and main tunnel intersection part,especially the side of the acute angle of intersection to guarantee the safety of the structure.The results above are worthful for design and construction of adits and main tunnels of underground engineering projects.