“Injection type rock bolt” has been finally succeeded in actual use after repeating tests and improvements under many kinds of the natural ground at the tunnel construction sites.
The principal components of this rock bolt are the bolt provided with a cloth bag fitted on one end of the bolt, injection tube and ventilation tube.
Advantage of “Injection type rock bolt” (1) Even long size bolt can be used. (2) The grout can be filled into the hole without any void. (3) It can be checked easily. (4) A high pullout resistance can be obtained quickly. This is explanation for the process of the development, component of the rock bolt, injecting material, grout pump units (both in the manual and automatic method), the pullout test, the working procedure and the execution.