Deformation, Failure Mechanism and Control Technology of Soft Rock Roadways Buried Under Coal Pillars: A Case Study
Abstract
1. Introduction
2. Engineering Background
2.1. Working Face Overview
2.2. Original Support and Deformation Characteristics of the Roadway
3. Deformation Mechanisms of Underlying Soft Rock Roadways in Close-Distance Coal Seam Mining
3.1. Mechanical Analysis of the Surrounding Rock of Underlying Roadways in Close-Distance Coal Seam Mining
- The calculation formula for the abutment stress in the plastic zone of the upper coal seam floor is as follows:
- The calculation formula for the abutment stress in the elastic zone of the upper coal seam floor is as follows:
- The calculation formula for the abutment stress in the in situ stress zone of the upper coal seam floor is as follows:
3.2. Numerical Analysis of Surrounding Rock of Underlying Roadways in Close-Distance Coal Seam Mining
3.2.1. Vertical Stress Distribution of Surrounding Rock in the CTR Under Different Working Conditions
3.2.2. Vertical Displacement Distribution of Surrounding Rock in the CTR Under Different Working Conditions
3.3. The Influence of Roadway Section Size on Surrounding Rock
3.4. Analysis of the Main Controlling Factors for the Failure of Underlying Soft Rock Roadways in Close-Distance Coal Seam Mining
- (1)
- In situ stress
- (2)
- The properties of surrounding rock
- (3)
- Cross-section size
4. Research on Control Strategies for Underlying Soft Rock Roadways in Close-Distance Coal Seam Mining
4.1. Section Optimization Scheme for Soft Rock Roadways
4.2. Support Optimization Scheme for Soft Rock Roadways
4.3. Numerical Analysis of the Optimization Scheme
4.4. Monitoring Results of Deformation of Surrounding Rock
5. Conclusions
- By considering the engineering geological conditions of the Danhou coal mine, a mechanical model of advance abutment stress transfer along the goaf floor was established. The theoretical analytical solution for vertical stress and horizontal stress at any point of the floor under the influence of advance abutment stress in close-distance coal seam mining was provided.
- The increase in abutment stress of the floor due to advance abutment stress transfer along the floor of the 5# coal seam resulted in further stress concentration of the surrounding rock of CTR in the 1# coal seam, leading to floor bulging and significant deformation on both sides.
- Numerical simulation results revealed significant changes in the stress and deformation of the surrounding rock with increasing distance between CTR and the goaf. The stress distribution exhibited an asymmetric–symmetric–asymmetric pattern, while the deformation showed an asymmetric distribution pattern that gradually decreased.
- The monitoring results of surrounding rock deformation demonstrated a 63.4% reduction in average deformation on both sides of CTR and a 93% decrease in average floor heave after implementing the new support scheme. This indicates that the technology effectively controls the deformation of the surrounding rock in soft rock roadways.
Author Contributions
Funding
Data Availability Statement
Conflicts of Interest
References
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Lithology | Thickness/m | Density/kg/m3 | E/GPa | µ | K/GPa | G/GPa | T/MPa | C/MPa | φ/° |
---|---|---|---|---|---|---|---|---|---|
Mudstone | 4.4 | 2550 | 3.08 | 0.2 | 1.71 | 1.28 | 0.58 | 1.56 | 26.9 |
Siltstone | 5.6 | 2540 | 5.22 | 0.22 | 3.11 | 2.14 | 1.05 | 3.12 | 22.3 |
Mudstone | 1.4 | 2550 | 3.56 | 0.2 | 1.98 | 1.48 | 0.54 | 1.58 | 19.9 |
Coal seam 4 | 1.1 | 1400 | 2.18 | 0.25 | 1.45 | 0.87 | 0.56 | 1.19 | 26.9 |
Mudstone | 16.0 | 2550 | 3.29 | 0.23 | 2.03 | 1.34 | 0.59 | 1.57 | 23.16 |
Siltstone | 2.2 | 2540 | 5.02 | 0.22 | 2.99 | 2.06 | 1.21 | 3.25 | 27.6 |
Mudstone | 4.6 | 2550 | 3.20 | 0.2 | 1.78 | 1.33 | 0.57 | 1.51 | 22.5 |
Siltstone | 0.6 | 2540 | 5.45 | 0.22 | 3.24 | 2.23 | 1.39 | 3.03 | 30.5 |
Coal seam 1 | 3.2 | 1400 | 2.07 | 0.25 | 1.38 | 0.83 | 0.52 | 1.15 | 27.7 |
Mudstone | 9.3 | 2550 | 1.96 | 0.2 | 1.09 | 0.82 | 0.5 | 1.54 | 21.8 |
Limestone | 20.0 | 2100 | 9.98 | 0.29 | 7.92 | 3.87 | 2.11 | 5.06 | 27.6 |
Conditions | Coal Seam Spacing Z0/m | Depth H/m | Lateral Pressure Coefficient/λ | Horizontal Distance L0/m | Remarks | |
---|---|---|---|---|---|---|
1 | 1-1 | 35 | 400 | 1.8 | 6 | Coal seam 5# has not been mined |
1-2 | 35 | 400 | 1.8 | 16 | ||
1-3 | 35 | 400 | 1.8 | 26 | ||
2 | 2-1 | 35 | 400 | 1.8 | 6 | Coal seam 5# has been mined |
2-2 | 35 | 400 | 1.8 | 16 | ||
2-3 | 35 | 400 | 1.8 | 26 |
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Bi, Y.; Li, Y.; Xu, F.; Zhu, L. Deformation, Failure Mechanism and Control Technology of Soft Rock Roadways Buried Under Coal Pillars: A Case Study. Processes 2025, 13, 2570. https://doi.org/10.3390/pr13082570
Bi Y, Li Y, Xu F, Zhu L. Deformation, Failure Mechanism and Control Technology of Soft Rock Roadways Buried Under Coal Pillars: A Case Study. Processes. 2025; 13(8):2570. https://doi.org/10.3390/pr13082570
Chicago/Turabian StyleBi, Yewu, Yichen Li, Feng Xu, and Lihua Zhu. 2025. "Deformation, Failure Mechanism and Control Technology of Soft Rock Roadways Buried Under Coal Pillars: A Case Study" Processes 13, no. 8: 2570. https://doi.org/10.3390/pr13082570
APA StyleBi, Y., Li, Y., Xu, F., & Zhu, L. (2025). Deformation, Failure Mechanism and Control Technology of Soft Rock Roadways Buried Under Coal Pillars: A Case Study. Processes, 13(8), 2570. https://doi.org/10.3390/pr13082570