Fragmented coal side anchor rod reinforcing method based on fracture fractal characteristics

Abstract

The invention relates to a fragmented coal side anchor rod reinforcing method based on fracture fractal characteristics. The method comprises the following steps that evaluating is carried out on the fractal characteristics of surrounding rock fractures in a drill hole section by section, stable anchoring section surrounding rock is found, the depth L of the drill hole is determined, and an 'inner pretightening force-mechanochemical anchoring force' combined lifting sleeve is designed. Under the chemical action of an anchoring agent, the combined lifting sleeve and the stable anchoring surrounding rock section are tightly anchored at the hole bottom of the drill hole, ab anchor rod body completely meshes with multi-line dense threads of the combined lifting sleeve, a mechanical supercharging section is expanded through a circular expanding device, the mechanical supercharging section is tightly attached to the inner wall of the drill hole, and therefore application of mechanical anchoring force is achieved; and the pre-tightening force applying position is changed, and therefore simultaneous loading and linkage lifting of the chemical anchoring force and the mechanical pre-tightening force at the same position are achieved, and both pre-tightening and anchoring positions of hte anchor rod are transferred to a stable anchoring area. In the process, the mechanical anchoring force is generated through mechanical force expansion and pushing, and the anchoring effect of the anchor rod is improved; and the anchorage effect of the anchor rod is improved, so that the value of the pre-tightening force is favorably kept.

Description

technical field [0001] The invention relates to the technical field of roadway support methods in mining engineering, in particular to a bolt reinforcement method for cracked coal sides based on the fractal characteristics of cracks. Background technique [0002] In the coal roadway during the coal mining process, because the side of the roadway itself is composed of coal with cracks, and affected by mining, the cracks in the coal side develop rapidly to form a certain range of fragmented coal, and sometimes the range of fracture will be far larger than conventional bolt lengths. In the fractured coal side, the bolt support is carried out according to the conventional technical procedures of drilling, anchoring, and pre-tightening. Large and deep gaps will cause a large amount of anchoring agent to be lost into the cracks, resulting in a reduction in the designed anchorage length and a decrease in anchorage quality; Rod pulling out, etc., even if the initial anchoring forc...

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Problems solved by technology

[0004] Aiming at the problems of insufficient anchoring force, poor pre-tightening and anchoring cooperation effect, and single pre-tightening form under the condition of the broken coal side, the patent of the present invention proposes a method for strengthening the broken coal side bolt based on the fractal characteristics of the cracks.

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