Main Roadway Stability Control via Pre-splitting Slits and Yielding Support
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Solution Overview
Problem
The coal mining main roadway in coal mining areas is prone to deformation and damage due to advanced abutment pressure and dynamic pressure disturbances from the working face, leading to instability and high maintenance challenges.
Innovation Solution
A surrounding rock stability control method involving reinforcing support on the roof and sides of the main roadway, digging a safety roadway with a protective coal pillar, performing slitting blasting to relieve pressure, and strategically extending pre-splitting slits to manage abutment pressure and mining disturbances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high-strength support structures (anchor cables, grouting anchor bolts, scaffolds) are used to reinforce the main roadway, then the roadway's resistance to dynamic pressure increases, but stress concentration and damage occur due to the confrontation between dynamic pressure and the rigid support structure
Solution Approach 1:
The patent changes the mechanical parameters of the support structure by using constant resistance anchor cables that maintain a fixed support force regardless of deformation. This allows the support to yield and deform plastically under dynamic pressure, converting the rigid support into a flexible system that can absorb energy without causing stress concentration.
Solution Approach 2:
The patent employs flexible support elements (anchor cables and bolts) that can deform and yield under load, replacing rigid support structures. These flexible elements allow the roadway to deform naturally under dynamic pressure while maintaining support, preventing the stress concentration that occurs with rigid supports.
2Productivity
If the working face advances closer to the main roadway to increase mining productivity, then coal extraction efficiency improves, but the main roadway experiences increased advanced abutment pressure and deformation
Solution Approach 1:
The patent applies preliminary reinforcement to the main roadway using constant resistance anchor cables and grouting anchor bolts before the working face advances. This pre-conditioning of the roadway allows it to withstand the upcoming advanced abutment pressure and dynamic pressure disturbances from coal mining operations.
Solution Approach 2:
The patent creates a dynamic support system that can adapt to changing stress conditions as the working face approaches. The constant resistance anchor cables and yielding support structures allow the roadway to deform and adjust dynamically to the moving pressure front, maintaining stability throughout the mining process.
3Productivity
If multiple working faces perform stoping and retreat operations, then coal production increases, but the main roadway experiences repeated dynamic pressure disturbances leading to cumulative deformation
Solution Approach 1:
The patent provides beforehand cushioning to the main roadway through reinforced support structures and protective coal pillars before multiple working faces begin their stoping and retreat operations. This pre-protection absorbs and dissipates the cumulative dynamic pressure disturbances from multiple mining cycles, preventing progressive deformation and extending the roadway's service life.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method reduces the influence of mining disturbances on the main roadway's stability, improves the yielding deformation capacity of the surrounding rock, and enhances the overall stability of the mining area main roadway by effectively managing abutment pressure and dynamic pressure.
Implementation Method 1
performing slitting blasting on the roof in the safety roadway, wherein a bidirectional tensile shaped charge device is used for shaped charge blasting
Implementation Method 2
a shaped charge blasting tube is used for loading 3 #emulsion explosive, and decoupling deck charging is used for blasting to form the pre-splitting slit
Data Source
AI summary
The present disclosure relates to a technical field of coal mining, in particular to a surrounding rock stability control method adapted for a coal mining area main roadway. The method comprises the following steps: reinforcing support on a roof and two sides of the mining area main roadway on a basis of an original support form; digging a safety roadway along a stop line of a present working face required by coal mine design, and supporting the safety roadway, wherein a protective coal pillar is formed between the safety roadway and the mining area main roadway; performing slitting blasting on the roof in the safety roadway, wherein blast holes are arranged on a roadway corner line on one side of the present working face to form a pre-splitting slit; and performing stoping at a next working face after completing coal mining at the present working face when stoping at the present working face advances to the safety roadway. By cutting the roof and relieving pressure at the stop mining line of the working face, an influence of mining disturbance on stability of the mining area main roadway in the stoping process of the working face is reduced, and by reinforcing support, a yielding deformation capacity of the mining area main roadway is improved, and the stability of the surrounding rock of the mining area main roadway is further improved.