Analysis and Design Optimization of Collapse Characteristics of Taojiakuang Tunnel Entrance Section

摘要

As a key risk source for tunnel engineering, the entrance section of tunnel is extremely easy to collapse. By analyzing the collapse of the entrance section of Taojiakuang Tunnel, the deformation characteristics before the tunnel collapsed were obtained. From the aspects of construction method and advanced support, three kinds of working conditions were considered to optimize the original design. From the perspective of safety and economy, the original advanced support design is unreasonable, and the conversion of the center cross diagram method to the center diagram method is not appropriate. For construction of tunnel entrances in weak broken rock, it is necessary to use the appropriate excavation method. When changing construction method, it is necessary to carry out sufficient demonstration and then re-construction to prevent the initial deformation of the surrounding rock from being too large and causing the tunnel to collapse. When encountering a weak broken zone, especially a rock formation boundary, it is necessary to increase the length of the advance support. The study provides a technical reference for similar projects.