Research on the pressure relief law of diamond beaded rope saw cutting seam - a numerical investigation

At a Glance

Metadata	Details
Publication Date	2024-04-23
Journal	Geomechanics and Geophysics for Geo-Energy and Geo-Resources
Authors	Jianguo Zhang, Xiaochuan Wang, Zhaolong Ge, Man Wang, Wei Wang
Institutions	Wuhan University, Shenhua Group (China)
Citations	2
Analysis	Full AI Review Included

Technical Analysis & Documentation: Diamond Beaded Rope Saw Cutting

Executive Summary

This technical analysis focuses on the numerical investigation of diamond beaded rope saw (DBRS) slotting as a pressure relief mechanism in low permeability coal seams, a critical application for mitigating high outburst risk in deep mining operations.

Core Application: DBRS cutting creates continuous slots to induce stress relief and enhance permeability in high-gas, low-permeability coal seams.
Mechanism Verified: The study confirms that DBRS slotting effectively reduces stress by damaging coal/rock integrity and facilitating stress redistribution via normal displacement and tangential slip along the contact surface.
Key Performance Driver: Pressure relief amplitude is significantly enhanced by increasing the coal seam inclination angle, rising from approximately 1.9% (horizontal, 0°) to 18.2% (inclined, 45°).
Material Dependency: The efficacy of the method relies directly on the robustness and cutting efficiency of the diamond beads used in the rope saw, which must withstand high shear and compressive forces.
Hardness Influence: Pressure relief is comparatively better in soft coal due to greater deformation and internal stress release compared to hard coal.
6CCVD Value Proposition: 6CCVD provides the high-toughness Polycrystalline Diamond (PCD) materials and custom fabrication services necessary to optimize DBRS bead performance for extreme geomechanical environments.

Technical Specifications

Parameter	Value	Unit	Context
Lab Model Size (L x W x H)	2500 x 200 x 1800	mm	Verification against experimental data
Diamond Yarn Diameter	2.2	mm	Used in laboratory model test
Numerical Model Size (L x W x H)	500 x 500 x 300	m	Large-scale engineering simulation
Coal Seam Inclination Range	0 to 45	°	Tested variable influencing pressure relief
Max Pressure Relief Amplitude	18.2	%	Achieved at 45° inclination
Min Pressure Relief Amplitude	1.9	%	Achieved at 0° inclination
Initial Ground Stress (Monitoring)	1.05	MPa	Reference stress after roadway excavation
Max Stress Concentration (45° seam)	17.3	MPa	Observed at the slit leading edge
Soft Coal Bulk Modulus (E)	1.0	GPa	Used for comparison of hardness effects
Hard Coal 2 Compressive Strength (σ_c)	19.7	MPa	Highest hardness group tested
Soft Coal Pressure Relief Amplitude	6.9	%	Amplitude in the middle of the slit
Hard Coal 2 Pressure Relief Amplitude	6.3	%	Amplitude in the middle of the slit

Key Methodologies

The research utilized a verified numerical simulation approach based on geomechanical principles to analyze stress distribution during DBRS slotting:

Theoretical Foundation: The model was constructed using the Superimposed Beam Theory (for layered rock strata) and the Contact Surface Model (for simulating interaction along the slit).
Numerical Platform: Finite difference software (FLAC3D) and distinct element software (UDEC) were employed for stress distribution analysis and verification.
Contact Modeling: The interface between the cut coal/rock masses was modeled using the Coulomb Friction Contact Surface Mesh to simulate normal embedding and tangential slip, which is critical for accurate pressure relief modeling.
Model Verification: Numerical results were validated against existing indoor laboratory model tests (Li et al. 2021) using a small-scale model (2.5 m length).
Parametric Analysis: The study systematically varied four key engineering parameters to determine their influence on pressure relief:
- Coal Seam Inclination (0°, 15°, 30°, 45°).
- Working Face Length (150 m, 200 m, 250 m).
- Coal Seam Hardness (Soft Coal, Hard Coal 1, Hard Coal 2).
- Slit Advancing Distance (50 m, 100 m, 250 m, 350 m).

6CCVD Solutions & Capabilities

The successful application of diamond beaded rope saw technology in geomechanics, as demonstrated by this research, relies fundamentally on the quality, consistency, and durability of the diamond cutting elements. 6CCVD is uniquely positioned to supply the advanced MPCVD diamond materials required to optimize DBRS performance and extend the limits of this pressure relief technique.

Applicable Materials

The diamond beads used in rope saws require exceptional toughness, thermal stability, and wear resistance to cut through hard rock and coal strata.

Application Requirement	6CCVD Material Solution	Rationale & Benefit
High-Toughness Cutting Elements	Polycrystalline Diamond (PCD) Plates	PCD offers superior fracture toughness and impact resistance essential for abrasive cutting applications like rock sawing. We supply plates up to 125mm for bead segment manufacturing.
Extreme Wear Resistance	High-Purity Single Crystal Diamond (SCD)	For specialized, high-precision cutting applications or extremely hard strata, SCD offers unparalleled hardness and thermal conductivity, ensuring longer tool life.
Custom Segment Fabrication	PCD/SCD Substrates (up to 10mm thick)	We provide custom-sized diamond segments or substrates tailored for integration into specific bead designs (e.g., 2.2 mm yarn diameter mentioned in the paper).

Customization Potential

The research highlights the need for precise control over the cutting process and the geometry of the slit. 6CCVD supports the development of next-generation DBRS tools through advanced customization:

Custom Dimensions: We supply PCD plates and wafers up to 125mm in diameter, allowing manufacturers to optimize the size and geometry of the diamond segments used in the beads for maximum cutting efficiency and stress relief.
Advanced Metalization: The bonding of diamond segments to the wire saw core is critical. 6CCVD offers in-house metalization services (Au, Pt, Pd, Ti, W, Cu) to ensure robust, high-strength interfaces capable of withstanding the high rotational speeds and shear forces encountered during deep seam cutting.
Surface Finish Optimization: While the paper focuses on bulk mechanics, the initial cut quality affects friction and stress transfer. We offer ultra-precise polishing (Ra < 5nm for inch-size PCD) for segments requiring specific surface characteristics.

Engineering Support

The findings regarding the superior pressure relief in inclined seams (up to 45°) and the difference between soft and hard coal necessitate tailored material selection. 6CCVD’s in-house PhD team specializes in correlating diamond material properties (e.g., grain size, binder content in PCD) with specific application requirements.

Material Selection for Geomechanics: We assist engineers in selecting the optimal PCD grade to balance toughness (for soft/fractured coal) and wear resistance (for hard rock interfaces), ensuring maximum operational efficiency in complex coal seam cutting projects.
Global Supply Chain: We offer reliable global shipping (DDU default, DDP available) to ensure timely delivery of custom diamond materials for international mining and geomechanical research projects.

For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.

View Original Abstract

Abstract As a new technology to mitigate the high outburst risk of the low permeability coal seam, it is essential to delve deeper into the law and mechanism of pressure relief associated with the diamond beaded rope saw slotting. The paper presents a numerical calculation model under small size that is based on the superimposed beam theory and the contact surface model. The model is compared with the experimental results of similar models in the laboratory to verify its applicability for simulating the numerical calculation of stress distribution in coal seam cut by diamond beaded rope saw. The study then goes on to investigate the influence of coal seam inclination, working face length, coal seam hardness, and seam advancing distance on the pressure relief effect of diamond beaded rope saw cutting seam under engineering scale. The mechanism of the diamond beaded rope saw cutting seam is also analyzed. The results indicate that the diamond beaded rope saw effectively reduces pressure in low permeability coal seams, with the impact range extending to the slit area. Additionally, stress concentration was observed at the front of the slit. Increasing the inclination of the coal seam, working face length, and advancing distance of the cutting seam enhances the pressure relief effect of the diamond beaded rope saw. The latter two factors’ influence is reflected in the direction along the working face and the direction of mining advance, respectively. The efficacy of pressure relief through this particular method is comparatively better in soft coal than in hard coal. This research is significant in promoting the widespread application of diamond beaded rope saws in the pressure relief of coal seam cutting.

Tech Support

Original Source

DOI: https://doi.org/10.1007/s40948-024-00798-2

References

2020 - Mechanical properties and stress-strain evolution mechanism of contact interface between upstream silt foundation and New Fill dam