Self-drilling rock anchor bolt is a bolting solution for unstable ground conditions such as sand, gravel, silt, and clays, and in soft to medium fractured rock formations. For engineering constructions facing such ground conditions, self-drilling anchor bolt system should be considered as the main solution. It is special designed for optimized installation, tailored to the project's needs. With a sacrificial drill bit an a hollow bar the system will at first drill a hole in collapsing soil or loose lock. After the drilling operation injecting cementitious grout or resin into the hollow bar and surrounding cavity, it's a top solution choice.
The operation is chasing free, drilling, anchoring and grouting can be done simultaneously. The accomplishment of the anchoring doesn’t need too much space so this system is also suitable and can work very well in narrow space. In this way the machinery and manpower requirements will be greatly optimized. According to different rock mass and ground conditions there corresponding drill bit design and diameter to choose. The anchor bolt can also be cut according to different demand or connected to required length by coupling.

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http://www.rockbolt.org/rock-bolt/r25-rock-bolt/