The Application of Self Drilling Anchor Bolts in Mining Roadway Supporting

The application of self drilling hollow bolts is becoming more and more widely. Self drilling hollow bolts can be seen in foundation engineering, slope engineering, tunnel and underground engineering, mine roadway, dam reinforcement and other projects.

With the increase of mining depth, the problem of difficult support for mine roadway engineering under complex geological conditions has become increasingly prominent, especially when the construction of large cross-section intersections encounters soft rock formations. How to effectively control the deformation and destruction of the surrounding rock of the roadway?

Use self drilling hollow bolts to pour cement grout into the fault fracture zone of the surrounding rock of the roadway, so that the grout fills the soft fracture zone of the fault. The cohesive force and internal friction angle of the roadway improve the strength and compressive resistance of the rock mass in the fault fracture zone. Under the combined action of the grouting bolt and the surrounding rock grouted, the deformation of the roadway surrounding rock is prevented and controlled.

The self drilling hollow bolt is used for grouting in the soft rock of the mine roadway, using the construction process of secondary grouting. First time, the grouting is performed while drilling, and the water-cement ratio of the grout is about 1:1; the second grouting is after the self drilling hollow bolt is drilled to the designed depth, and the water-cement ratio of the grout is about 0.45~0.6:1. Both grouting are under pressure grouting, which can make the grout fully fill the cracks of the rock and soil, stabilize the internal structure of the broken rock, and enhance the anchoring force.

Self drilling hollow anchor rod is an anchor rod that combines drilling, grouting, and anchoring functions into one. It can ensure the anchoring effect under complex stratum conditions, and has the characteristics of reliability, efficiency, and simplicity.

1. The drill rod is the anchor rod. No casing is required for wall protection in strongly weathered rock, broken rock layer, cobblestone layer, etc., and the grouting and anchoring process can be completed in one drilling to ensure the anchoring and grouting effect.

2. Pressure and high-efficiency grouting, filling cracks, consolidating rock mass and soil, controlling groundwater, having a good grouting diffusion radius and reliable anchoring quality. The self drilling hollow anchor rod is hollow in the rod body. The drill rod is the anchor rod and the grouting pipe. The mortar enters from the end of the anchor rod, passes through the hollow and hollow drill bit, overflows from the front end of the anchor rod, and returns to the tail for grouting to ensure complete filling of the anchor. The rod turnover gap consolidates the rock mass.

3. The self drilling hollow anchor rod has continuous threads throughout the body, which can be cut or connected at will, suitable for construction in narrow work sites, especially mine tunnels.

The application of self drilling hollow bolts in mine tunnels can effectively control the deformation of the surrounding rock of the tunnel, and ensure the stability of the project and the safety of construction.