How To Fix The Roof Bolts?

There are several methods of mechanical anchoring, early strength coiling and grout injection. The operation methods are as follows:

After the top plate is drilled, the mechanical expansion head on the top of the anchor rod is drilled to the bottom of the roof to anchor the expansion shell. Then insert the early-strength coil, and then insert the anchor rod to bond and anchor. After pouring the cement mortar, insert the anchor rod to bond and fix it. After the hollow bolt is inserted into the borehole, cement slurry is injected and fixed.

The principle of bolt combination arch is that when prestressed bolts are installed in the fracture zone of the surrounding rock of the supply roadway, the compressive stress distributed in the form of cones will be formed at both ends of the rod. If the anchor rod group is arranged along the top plate, the compressive stress cones formed by each anchor rod will be staggered and overlapped, forming a pressure-bearing arch that prevents the rupture zone from spreading, which can withstand the radial load applied by the broken rock above it. The pre-tightening force along the axial direction of the anchor rod produces hoop stress in the combined arch, which significantly improves the stress state of the pressure-bearing arch, and changes the state of the surrounding rock from uniaxial or biaxial to triaxial compression.

In this way, a uniformly compressed continuous bearing zone is formed in the surrounding rock, thereby greatly improving the bearing capacity of the combined arch.