Principles of using U-shaped Tunnel Roof Supports.
1. New Austrian support theory for Tunnel Roof Supports: smooth blasting is used; early-strength shotcrete is used to seal the surrounding of the roadway in time, and close support is implemented; bolt-and-shot support is used to actively reinforce the surrounding rock and improve its self-supporting capacity. Form a bearing circle in the surrounding rock; implement secondary support; implement grouting reinforcement for broken surrounding rock; implement dynamic design and dynamic construction, etc.
2. The theory of Steel Mine Supports combined support: For complex and difficult roadways, it is difficult to effectively control the deformation of the surrounding rock only by increasing the rigidity of the support body.
3. The theory of loose circle support of Steel Mine Supports: After road excavation, a loose circle generally appears. The maximum deformation load of the surrounding rock is the crushing deformation during the generation of the loose circle, and the crushing deformation of the rock during the rupture of the surrounding rock is the support object. The larger the loose circle is, the larger the crushing and bulging deformation, the larger the deformation of the surrounding rock, and the more difficult the roadway support is.
4. The theory of strengthening the surrounding rock strength of the Steel Mine Supports: strengthen the stress state of the surrounding rock, increase the confining pressure, and improve the bearing capacity of the surrounding rock.
