Extensible Reaming Self-Anchoring Anchor Rod for Coal Roadway Stability
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Solution Overview
Problem
Current anchor rod supporting methods in coal roadways face challenges such as poor adaptability to soft coal, high deformation, side falling, hole collapse, and limited tunneling speed due to fixed rod lengths and complex structures, with existing solutions like resin anchoring and self-drilling rods being inefficient and costly.
Innovation Solution
An extensible reaming self-anchoring anchor rod with a simple drill bit, modular rod sections, and a pre-tightening device allows for adjustable length and reinforcement, integrating drilling and anchoring through a big helical structure that self-embeds in coal mass, reducing the need for resin and enhancing adaptability and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If resin anchoring technique is used for coal roadway sides, then anchoring is achieved, but adaptability to soft and loose coal mass is poor and anchoring effect is reduced
Solution Approach 1:
The patent changes the anchoring mechanism from chemical bonding (resin) to mechanical interlocking (screw threads). The screw anchor rod uses threaded structure that mechanically engages with the coal mass, providing reliable anchoring without depending on chemical bond strength, thus improving adaptability to soft and loose coal conditions
Solution Approach 2:
The patent replaces the chemical anchoring system (resin anchoring agent) with a mechanical anchoring system (screw anchor rod with threads). The threaded structure provides mechanical interlocking with the coal mass, eliminating the need for chemical bonding and improving reliability in soft coal conditions
2Force
If resin anchoring technique is used, then anchoring is provided, but anchor bonding force is too low to restrain coal mass deformation
Solution Approach 1:
The patent changes the force transmission mechanism from chemical bonding force to mechanical thread engagement force. The screwed anchor rod generates high mechanical interlocking force through thread engagement with the coal mass, providing sufficient restraining force to prevent coal mass deformation and side falling
3Ease of manufacture
If drilling in coal walls is performed with resin anchoring, then anchor holes are created, but hole collapse occurs easily and drilling probability is low
Solution Approach 1:
The patent combines the drilling operation and anchoring operation into a single integrated process. The screw anchor rod is driven directly into the coal mass using a drilling machine, creating the anchor hole and installing the anchor in one continuous operation, eliminating the separate steps of drilling, clearing, and inserting resin, thus preventing hole collapse
Solution Approach 2:
The screw anchor rod structure itself serves dual functions: it creates its own anchor hole through the drilling action and simultaneously provides the anchoring function through its threaded structure. The helical threads of the screw rod act as both the drilling cutting edges and the anchoring engagement elements, eliminating the need for separate hole creation and anchoring steps
4Productivity
If resin anchoring technique is used, then anchoring is achieved, but roadway tunneling speed is severely limited due to multiple process steps
Solution Approach 1:
The patent merges drilling, hole clearing, and anchor installation into a single integrated operation. The screw anchor rod is driven directly into the coal mass using a drilling machine in one continuous process, eliminating the multiple separate steps required by resin anchoring (drilling, clearing dust, inserting cartridge, injecting resin, curing), thus significantly improving tunneling speed
Solution Approach 2:
The screw anchor rod installation maintains continuous useful action throughout the process. The drilling machine continuously drives the screw rod into the coal mass without interruption for clearing, resin injection, or curing等待, keeping the productive action continuous and eliminating idle time between operations
5Adaptability or versatility
If fixed length anchor rods are used, then installation is simplified, but adaptability to local areas with varying anchorage requirements is poor
Solution Approach 1:
The patent segments the anchor rod into multiple drillable sections that can be assembled in series. Each section has external threads that engage with the previous section, allowing the anchor rod to be extended to various lengths by adding or removing sections, thus adapting to different anchorage requirements while maintaining a relatively simple modular structure
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 solution simplifies side supporting, improves adaptability to coal deformation, reduces construction time, and allows for adjustable anchorage length, effectively preventing side falling and enhancing tunneling speed by integrating drilling and anchoring, while reducing engineering workload and costs.
Implementation Method 1
the big helical structure accomplishes secondary reaming and self-anchoring in the drilling process
Implementation Method 2
a big helical structure outside of it
Data Source
AI summary
Provided is a mounting method for an extensible reaming self-anchoring anchor rod, which is especially applicable to roadway construction in coal mines. A big helical structure is arranged on two rod sections of a sectional type anchor rod, a simple drill bit drills and reams a bore and cuts the coal mass in one operation, the outer diameter of the simple drill bit is smaller than the outer diameter of the big helical rod body, and the big helical structure accomplishes secondary reaming, self-drilling and self-anchoring in the drilling process; the big helical structure inhibits propagation and development of sheet cracks of the coal wall in the radial direction, and is embedded in the coal mass through a self-stabilization process of the rock mass.