Three dimensional anchor cable bolting technology in heading

Abstract

A coal bed alley way three dimensional anchor cable net support technology is best adapted for supporting the thick rock layer with soft top board in mine. When adopting the anchor cable to fix the top board rock layer, the anchor rods at two ends of the same top board are connected to two adjacent anchor cable in level plane cross direction to integrate all supports in order to form a strict 'support net'. The anchor cable can reinforce the top board rack layer in vertical direction, and can be connected to two anchor rods and the front and rear adjacent anchor cables in level direction. The alley way top board rock layer can bear a three dimensional restraining force, so the top board rock layer is prevented from being damaged earlier, the reliability and safety of the support whole body are increased, the difficult problem the bottom construction top board risk when exploiting thick and very thick soft coal layer in mine is solved. The construction technics is simple, convenient in locale operation and has broad practicability.

Description

1. Technical field [0001] The invention relates to a three-dimensional anchor cable network support technology for coal seam roadways, and is especially suitable for the support of mining thick and extra thick soft coal seam roadways, and is also suitable for the reinforcement of geotechnical engineering. 2. Background technology [0002] In coal roadway bolt support, especially in extra thick and soft coal seam roadway, due to the excavation of coal roadway, the original stress balance state and distribution have been changed, so that the coal rock on the surface of the roadway is changed from a three-way stress state to a two-way stress state , under the action of mine pressure, the coal and rock on the surface of the roadway must seek and reach a new stress balance state. This evolution process is the process of (radial) expansion, deformation and horizontal movement of the coal and rock in the roadway. Improve the radial compressive strength of coal rock, but cannot impr...

AI Technical Summary

Problems solved by technology

[0002] In coal roadway bolt support, especially in ultra-thick and soft coal seam roadway, the original stress balance state and distribution have been changed due to the excavation of coal roadway, so that the coal rock on the surface of the roadway is changed from a three-dimensional stress state to a two-direction stress state , under the action of mine pressure, the coal and rock on the surface of the roadway should seek and reach a new state of stress balance. This evolution process is the process of (radial) expansion, deformation and horizontal movement of the coal and rock in the roadway. Improve the radial compressive strength of coal and rock, but cannot improve the tangential and axial compressive strength of coal and rock, so the coal and rock in the roadway will have uneven stress, causing the coal and rock in the roadway to move towards the area with low stress, making the The pressure and deformation in this area increase, especially the coal rock in the middle between the bolts is the weakest and the deformation is the largest

When the distance between the supporting anchor rods is large, the rock mass at this position is under tensile stress, and the tensile strength of the coal and rock is very low. Once a breach occurs, the surrounding coal and rock will flow here under the action of mine pressure , so that the prestress of the bolt is reduced or lost, resulting in an increase in the deformation of the coal and rock on the surface of the roadway. If the control is not good, it may also cause a roof fall accident

At the same time, each anchor is isolated from each other and has no connection with each other. Once a certain anchor fails under high stress, the surrounding anchors will gradually lose their supporting function under the influence of it, and then develop into a large area support failure

Images