Influence of Excavation of Horizontal Adit Tunnel on Main Tunnel and Safety Analysis

For the influence of horizontal adit tunnel on the main tunnel, taking a tunnel as an example, MIDAS finite element software is used to analyzes the displacement and stress state of the primary support and secondary lining structure of the main tunnel before and after excavation, gives the local structural safety factor at the junction of the two, and analyzes the safety of the lining structure. The results show that: (1) After the main tunnel lining is removed, the lining has a certain displacement to the free face, the maximum is 55.3 mm, and the displacement changes little after the lining of the horizontal adit tunnel; (2) The safety factor calculation of the main tunnel lining at the junction, except the inverted arch area of primary support, all other parts meet the specification requirements.