Compared with other rigid supports, Tunnel Roof Support has the ability to be contracted, stable and reliable. It adapts to the load and deformation of soft surrounding rock, has high section utilization, convenient support for branch Support Arch , small maintenance, high recovery rate of bracket recovery, and reduced pit. Wood use, environmental benefits are very obvious.
The optimal stress state of Tunnel Roof Support is that it is evenly pressed after the wall is filled and compacted. When the pressure value of the surrounding rock on the Tunnel Roof Support reaches a certain value, the bracket will compress and make the surrounding rock act on the tunnel. The pressure on the Roof Support drops, thereby preventing the surrounding rock pressure from being greater than the bearing capacity of the Tunnel Roof Support.
As the main type of Tunnel Roof Support for manufacturing roadway shrinkable metal brackets, U-shaped steel is widely used at home and abroad. However, due to the inconsistent understanding of the performance and requirements of U-shaped steel itself, the cross-sectional shape, geometric parameters and materials of U-shaped steels vary from country to country. The U-shaped steel models produced in China mainly include 18U, 25U, 29U and 36U. The first two are 60s products, which are waist positioning; the latter two are 80s products, which are ear positioning. U18 is rarely produced due to its low carrying capacity.
