An expandable prestressed anti-tension bolt bundle for gob-side entry retention and its use method

Abstract

The invention discloses an expandable prestressed double-tensioned bolt bundle for gob-side entry retention and a use method thereof, which includes a bolt body, prestressed steel bars, eight-point braces and connecting steel bars. An integrated structure is composed of two connecting steel bars, and then the three eight-point braces of the integrated structure are slid on the anchor body through the front slider and the rear slider, and are in a closed state; then the prestressed steel bars are respectively passed through each of the three Split braces and two inner locks; then pass the preliminarily assembled anti-tension anchor rods through the filling bag, so that the three eight-point braces are in the filling bag; then apply tension to the connecting steel bars through the drawing equipment, where the connecting steel bars are subjected to tension Each eight-point brace will change from a closed state to a stretched state, and then each prestressed steel bar will be stretched and deformed, and finally reach a fully stretched state; Stress, after completion, inject high-water filling material into the filling bag, and form a filling body after solidification.

Description

technical field [0001] The invention relates to an expandable prestressed tensioning bolt bundle for gob-side entry retention and a method for using it, belonging to the technical field of coal mine safety mining. Background technique [0002] Because the high water filling material is used for goaf filling, it has the advantages of simple process, fast setting speed and stable performance. Therefore, it has been widely used in coal industry roadside filling support, goaf plugging and fire extinguishing, flame retardant, well wall thickness filling support, etc. Its construction is to inject the slurry of high water filling material into the goaf and set the pull anchor rod in the slurry. After the slurry is solidified, a filling body is formed, and the pull anchor rod is in the filling body to strengthen the support. However, when the existing high-water filling materials are used for filling in the gob-side entry retention, the double-pull bolts are single-piece double-pu...

AI Technical Summary

Problems solved by technology

However, when the existing high-water filling materials are used for filling in the gob-side entry retention, the double-pull bolts are single-piece double-pull bolts. After filling, the contact area between the single double-pull bolts and the filling body is small, and the filling body can be controlled The deformation range is limited, resulting in different deformation resistance at different positions of the filling body. The middle position of the two single-unit pull anchors in the filling body has a certain distance from the two single-body pull anchors, resulting in the filling body being in the middle of the anchor rod. When the roof is pressed, the two single-body tension anchors cannot strengthen the support, resulting in cracks, outward bulging and deformation, and finally reducing the strength of the filling body. Practice has proved that applying prestress can improve the filling body Mechanical properties, but because the tension anchor is placed on the steel mesh, the reinforcement mesh cannot exert a reaction force on the prestress of the tension anchor, resulting in the inability to apply prestress to the tension anchor to achieve the desired effect

Images