How to operate mining anchor rods is strictly prohibited during use

How to operate mining anchor rods is strictly prohibited during use

Mining anchor rods are an important part of coal mining and play a crucial role in supporting the ore body. Therefore, it is necessary to understand the characteristics of anchor rods and the methods of using them. It is a prerequisite to play the role of anchor rod support and ensure the stability of the ore body. Understanding some precautions for using anchor rods can prevent accidents from occurring.

Operating steps for mining anchor rods:

(1) The tail of mining anchor rods is the part of the entire rod body that is subjected to complex forces and is prone to damage. A stress analysis was conducted on the threaded section of the anchor rod, and it was found that the local stress concentration in the threaded section was 2-3 times due to the change in diameter; Due to the unreasonable rotation of the spherical surface between the tray and the ball pad, self-locking occurs between the two spherical surfaces, leading to a sharp deterioration or even fracture of the anchor rod's stress.

(2) When the installation angle of mining anchor rods is too large and the tensile stress reaches a certain value, long-term loading can cause the threaded section at the tail of the anchor rod to bend, crack or even fracture; When the applied pre tightening torque is greater than 600N'm, the composite stress on the anchor rod is close to the yield stress of the material. The anchor rod first produces cracks from the bending point, and then the cracks expand, causing the anchor rod to fracture before reaching the breaking tension.

(3) The combination of tension bending torsion, tension shear torsion, and tension bending shear torsion is a common stress state during the installation of underground anchor rods. The closer to the fixed end, the greater the stress, so the unfavorable position is the fixed end.

(4) Optimization schemes such as vertical installation of anchor rods, redesign of centering ball pads, full length anchoring of anchor rod prestressing, and adjustment of anchor rod pre tightening torque to 400N. m are proposed to reduce the impact of harmful forces on the rod body.