Composite Grouting Pipe for Coal Seam Reinforcement
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Solution Overview
Problem
Traditional grouting methods in internal-staggered split-level coal mining struggle with multi-angle grouting and limited reinforcement of the coal seam due to the large 120° interval of grouting holes and uniform rock bolt lengths, which restricts effective support and energy efficiency.
Innovation Solution
A method and device employing a composite grouting pipe with a hollow rock bolt and staggered arrangement of grouting holes at varying angles, allowing for multi-angle and omni-directional grouting, along with staggered rock bolt placement to enhance coal seam reinforcement between adjacent gateroads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a three-hole grouting pipe with 120° interval is used, then sufficient grouting pressure can be provided to reach deep coal seam cracks, but multi-angle grouting on the coal seam around the grouting pipe cannot be realized
Solution Approach 1:
The grouting pipe is divided into multiple independent holes (at least three holes) arranged at different angles around the pipe circumference. Each hole can independently deliver grout at different angles, allowing the system to achieve multi-angle grouting while maintaining sufficient pressure through the selective activation of individual holes based on crack orientation and depth requirements.
Solution Approach 2:
The grouting holes are arranged in three-dimensional space around the grouting pipe, extending in multiple directions (upward, downward, laterally) rather than being confined to a single plane. This spatial arrangement enables grout to be injected into cracks propagating in various orientations, achieving omni-directional reinforcement of the coal seam.
2Ease of manufacture
If rock bolts of uniform length are used, then installation is simplified, but only part of the coal seam around the roadway can be reinforced
Solution Approach 1:
Rock bolts of different lengths are selected and installed at different locations around the roadway based on the specific reinforcement needs of each area. Longer bolts are used where deeper reinforcement is required, while shorter bolts suffice for areas with shallower cracks or lower stress concentrations. This localized customization maximizes the reinforced coal seam area while maintaining installation feasibility.
3Productivity
If the inlet air gateroad is excavated immediately after the return air gateroad, then construction progress is accelerated, but the return air gateroad cannot be stabilized before next heading face excavation
Solution Approach 1:
Grouting operations are performed in advance on the return air gateroad before the inlet air gateroad is fully excavated or before the next heading face begins excavation. This preliminary reinforcement stabilizes the coal seam and roadway structure, ensuring safety and reliability while allowing subsequent excavation activities to proceed without waiting for prolonged stabilization periods, thus maintaining construction productivity.
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 enables stable and efficient reinforcement of the coal seam with improved grouting pressure and reduced workload, providing significant economic benefits and enhanced support without additional rock bolts.
Implementation Method 1
a grouting pump, and a deliver pipeline, wherein the drilling rig and the drilling tool are configured for hole-forming; the stirrer is configured to prepare a grout; the delivery pipeline is configured to transport the grout; and the grouting pump is configured to provide a pressure to transport the grout to a target position through the delivery pipeline
Data Source
AI summary
A method for carrying out grouting between adjacent gateroads in internal-staggered split-level coal mining. A return air gateroad of a stoping face and an inlet air gateroad of a heading face are not on the same level. The return air gateroad of the stoping face is arranged along a roof of a coal seam. The inlet air gateroad of the heading face is arranged along a floor of the coal seam. There is a height difference between the return air gateroad and the inlet air gateroad in a vertical direction. During the construction process, the inlet air gateroad is excavated at a delay distance of 180-200 meters from the return air gateroad. The drilling and grouting are performed while excavating the roadway, where grouting holes are arranged in a single row. A device for implementing the method is also provided.