Tunnel Anchor Cable Shear Locking for Coal-Rock Interface Stability
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Solution Overview
Problem
Existing tunnel support systems in coal mines face significant shear forces due to non-equilibrium deformations of coal walls and roof/floor layers, leading to anchor cable failure and reduced support performance.
Innovation Solution
An internal and external coupling shear resistance locking control system is implemented, comprising shear misalignment tolerance cavities, shear resistance steel strips, compensating pull rods, and monitoring systems to manage shear displacements and forces, ensuring stable anchoring and monitoring of anchor cables.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If anchor cables are arranged obliquely to penetrate roof and floor rock layers for stable anchoring, then anchoring stability is improved, but shear forces on anchor cables increase causing cable breakage
Solution Approach 1:
The anchor cable system is segmented into multiple components: the anchor cable itself, anchoring agents for embedding in rock layers, shear resistance steel strips for force distribution, and compensating pull rods for active adjustment. This segmentation allows each component to handle specific forces, preventing cable breakage while maintaining stability.
Solution Approach 2:
Shear resistance steel strips and anchoring agents act as intermediaries between the oblique anchor cables and the rock layers. These intermediaries distribute and balance the shear forces generated by oblique arrangement, protecting the anchor cables from excessive shear stress while maintaining the stability benefits of rock layer penetration.
2Force
If strong anchor cables are arranged in soft coal body for support, then support force is improved, but anchor failure occurs due to weak foundation
Solution Approach 1:
The anchoring system is divided into anchoring agents that embed in the coal body and anchor cables that provide support force. The anchoring agents act as a distributed foundation, spreading the load across multiple points in the soft coal body, preventing anchor failure while maintaining support force.
Solution Approach 2:
The system uses composite anchoring agents combining multiple materials with different properties to create a reliable foundation in soft coal. The composite structure allows the anchoring agents to adapt to the weak coal foundation while transferring support forces effectively to the anchor cables.
3Reliability
If large area grouting is performed on soft coal walls to improve anchoring, then anchoring coverage is improved, but construction cost and time increase significantly
Solution Approach 1:
Instead of uniform large-area grouting, the system applies anchoring agents locally at specific anchor cable positions. The anchoring agents are concentrated at critical anchoring points where they provide maximum reliability, eliminating the need for time-consuming full-area grouting while maintaining anchoring reliability.
Solution Approach 2:
The anchoring agents are designed as disposable, pre-packaged materials that are installed quickly at each anchor point. This eliminates the need for extensive grouting operations, significantly reducing construction time and cost while providing sufficient anchoring reliability through localized application.
4Stability of the object's composition
If steel strips or channel steels are used to connect oblique anchor cables, then structural connection is improved, but shear damage occurs at anchor cable channels
Solution Approach 1:
Shear resistance steel strips serve as intermediaries between the oblique anchor cables and the connecting structure. These strips are specifically designed to resist shear forces, absorbing and distributing the shear stresses that would otherwise damage the anchor cable channels, while maintaining stable structural connection.
Solution Approach 2:
The steel strips are designed with specific geometric parameters and material properties optimized for shear resistance. By changing the parameters of the connecting elements to prioritize shear resistance, the system maintains structural connection stability while preventing shear damage to anchor cable channels.
Data Source
AI summary
An internal and external coupling shear resistance locking control system and monitoring method of tunnel surrounding rocks, comprises an internal shear resistance and monitoring system of tunnel surrounding rocks, an external shear resistance and monitoring system of tunnel surrounding rocks, a relative shear displacement monitoring system of the tunnel walls and the roof and floor layers, and an anchor agent installation system; holes are expanded in the anchor cable drilling holes passing through coal-rock interface areas of the coal walls and roof and floor rock layers to form shear misalignment tolerance cavities; monitoring pressure values of measuring bags and liquid discharge in the shear misalignment tolerance cavities to determine shear deformations of the shear misalignment tolerance cavities, monitoring forces on anchor cables, compensating pull rods and shear resistance steel strips, and adjusting the shear resistance of the anchor cable and steel belt through the compensation rod structure.