Study on the Stability Principle of Mechanical Structure of Roadway with Composite Roof
Abstract
:1. Introduction
2. Mechanical Structure Model of Composite Roof
3. Damage Model of Composite Roof Based on Weibull Distribution
- (1).
- The micro-elements conform to the generalized Hooke’s law.
- (2).
- The micro-element failure is in accordance with Mises yield criterion.
4. Stability of Composite Roof and Its Influencing Factors
4.1. Deflection and Stress Distribution of Composite Roof
4.2. Determination of Separation and Instability of Composite Roof
4.3. Influencing Factors of Composite Roof Stability
- (1).
- Roadway width
- (2).
- Overlying strata load
- (3).
- Elastic modulus
- (4).
- Shape parameter
- (5).
- Scale parameter
5. Influence of Bolt Support on Stability of Composite Roof
6. Conclusions
- (1)
- Based on Weibull statistical distribution, generalized Hooke’s law and Mises yield criterion, the expression of damage parameters of composite roof is obtained. The influence of Weibull shape parameters and scale parameters on damage parameters is discussed. When the shape parameter is 1, the damage parameter of composite roof increases exponentially with the increase in principal strain. When the shape parameter is greater than 1, the damage parameter of composite roof increases exponentially with the increase in principal strain, when the principal strain is greater than 0.5, the larger the shape parameter is, the larger the damage parameter is. When the principal strain is less than 0.5, the smaller the shape parameter is, the larger the damage parameter is. Under the condition of different scale parameters, with the increase in principal strain, the growth rate of damage parameter of composite roof is greater and the stability is faster.
- (2)
- Based on the theory of infinite length plate, the expressions of deflection and separation of each layer of composite roof are derived, and the critical load expression of each layer is given. The influence law of the width of coal roadway, the load of overlying strata, elastic modulus, shape parameters and scale parameters on the stability of composite roof is discussed. The maximum subsidence and separation of each layer of composite roof is directly proportional to the fourth power of roadway width. The large section of coal roadway with composite roof significantly increases the subsidence and separation of each layer, and the stability of composite roof decreases sharply; the load of overlying strata is proportional to the buried depth of coal roadway with composite roof, and the maximum deflection of each layer increases linearly with the increase in buried depth of coal roadway with composite roof. When the buried depth is shallow, the subsidence of mudstone is small and easy to maintain. However, after deep mining, the deformation of each layer is serious, and it is easy to lose stability and cause failure; with the increase in elastic modulus, the maximum deflection of each layer decreases continuously, and the reduction range decreases continuously; when the shape parameter increases from 1 to 2, the maximum deflection of each layer decreases sharply, and then with the increase in shape parameters, the decrease in maximum deflection of each layer becomes smaller and smaller. The larger the shape parameter is, the stronger the stability of composite roof is; the influence of scale parameters on the stability of each layer is consistent with the shape parameters.
- (3)
- Bolt is a supporting form with both supporting and reinforcing functions. After using bolt support, the separation between layers of composite roof is effectively reduced, and the stability of composite roof is greatly enhanced. For the surrounding rock control of roadway with composite roof, the active support technology with bolt as the core should be adopted.
Author Contributions
Funding
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
- Jun, X.; Liang, Y.P.; Zou, Q.L.; Li, L.; Li, X.L. Elimination of coal and gas outburst risk of low-permeability coal seam using high-pressure water jet slotting technology: A case study in Shihuatian Coal Mine in Guizhou Province, China. Energy Sci. Eng. 2019, 7, 1394–1404. [Google Scholar] [CrossRef]
- Teng, J.W.; Qiao, Y.H.; Song, P.H. Analysis of exploration, potential reserves and high efficient utilization of coal in China. Chin. J. Geophys. 2016, 59, 4633–4653. [Google Scholar]
- Wang, Q.; Song, X.X.; Liu, Y. China’s coal consumption in a globalizing world: Insights from Multi-Regional Input-Output and structural decomposition analysis. Sci. Total Environ. 2020, 711, 134790. [Google Scholar] [CrossRef]
- Yang, Y.X.; Zheng, X.Y.; Sun, Z. Coal Resource Security Assessment in China: A Study Using Entropy-Weight-Based TOPSIS and BP Neural Network. Sustainability 2020, 12, 2294. [Google Scholar] [CrossRef] [Green Version]
- Zhang, H.L.; Shen, L.; Zhong, S.; Elshkaki, A. Coal resource and industrial structure nexus in energy-rich area: The case of the contiguous area of Shanxi and Shaanxi Provinces, and Inner Mongolia Autonomous Region of China. Resour. Policy 2020, 66, 101646. [Google Scholar] [CrossRef]
- Hu, X.S.; Wu, Z.Z.; Wang, R.J.; Duoc, Y.Q. Statistical analysis of coal mine accidents in China from 2005–2013. Oper. Environ. Mine Health Saf. Prac. Innov. 2016, 527–530, 2213–2221. [Google Scholar]
- Jiao, Y.Y.; Wang, Z.H.; Wang, X.Z.; Adoko, A.C.; Yang, Z.X. Stability assessment of an ancient landslide crossed by two coal mine tunnels. Eng. Geol. 2013, 159, 36–44. [Google Scholar] [CrossRef]
- Li, Q.S.; He, X.; Wu, J.H.; Ma, S. Investigation on coal seam distribution and gas occurrence law in Guizhou, China. Energy Explor. Exploit. 2018, 36, 1310–1334. [Google Scholar] [CrossRef]
- Xu, Y.L.; Pan, K.R.; Zhang, H. Investigation of key techniques on floor roadway support under the impacts of superimposed mining: Theoretical analysis and field study. Environ. Earth Sci. 2019, 78, 1–14. [Google Scholar] [CrossRef]
- Yan, H.K.; He, H.F. The Analysis of Coal Mine Safety Production Risk in Guizhou Province. Chin. Perspect. Risk Anal. Crisis Response 2010, 13, 1084–1089. [Google Scholar]
- Zhang, Z.Z.; Deng, M.; Bai, J.B.; Yu, X.Y.; Wu, Q.H.; Jiang, L.S. Strain energy evolution and conversion under triaxial unloading confining pressure tests due to gob-side entry retained. Int. J. Rock Mech. Min. Sci. 2020, 126, 10. [Google Scholar] [CrossRef]
- Chang, J.C.; He, K.; Yin, Z.Q.; Li, W.F.; Li, S.H.; Pang, D.D. Study on the Instability Characteristics and Bolt Support in Deep Mining Roadways Based on the Surrounding Rock Stability Index: Example of Pansan Coal Mine. Adv. Civ. Eng. 2020, 2020, 8855335. [Google Scholar] [CrossRef]
- Zhang, J.P.; Liu, L.M.; Shao, J.; Li, Q.H. Mechanical Properties and Application of Right-Hand Rolling-Thread Steel Bolt in Deep and High-Stress Roadway. Metals 2019, 9, 346. [Google Scholar] [CrossRef] [Green Version]
- Hao, X.J.; Wang, S.H.; Jin, D.X.; Ren, B.; Zhang, X.Y.; Qiu, K.L.; Fan, Y.J. Instability Process of Crack Propagation and Tunnel Failure Affected by Cross-Sectional Geometry of an Underground Tunnel. Adv. Civ. Eng. 2019, 2019, 17. [Google Scholar] [CrossRef]
- Zheng, X.G.; Feng, X.W.; Zhang, N.; Gong, L.Y.; Hua, J.B. Serial decoupling of bolts in coal mine roadway supports. Arab. J. Geosci. 2015, 8, 6709–6722. [Google Scholar] [CrossRef]
- Kang, H.; Wu, Y.; Gao, F.; Lin, J.; Jiang, P. Fracture characteristics in rock bolts in underground coal mine roadways. Int. J. Rock Mech. Min. Sci. 2013, 62, 105–112. [Google Scholar] [CrossRef]
- Zhang, Y.; Xu, H.C.; Song, P.; Sun, X.M.; He, M.C.; Guo, Z.B. Stress Evolution Law of Surrounding Rock with Gob-Side Entry Retaining by Roof Cutting and Pressure Release in Composite Roof. Adv. Mater. Sci. Eng. 2020, 2020, 1961680. [Google Scholar] [CrossRef]
- Yu, Y.; Wang, X.Y.; Bai, J.B.; Zhang, L.Y.; Xia, H.C. Deformation Mechanism and Stability Control of Roadway Surrounding Rock with Compound Roof: Research and Applications. Energies 2020, 13, 1350. [Google Scholar] [CrossRef] [Green Version]
- Pavlovic, A.; Sintoni, D.; Fragassa, C.; Minak, G. Multi-Objective Design Optimization of the Reinforced Composite Roof in a Solar Vehicle. Appl. Sci. 2020, 10, 2665. [Google Scholar] [CrossRef]
- Xiong, X.Y.; Dai, J.; Wang, X. Comprehensive Analysis of Stability of Coal Seam Composite Roof Based on Analytic Hierarchy Process. Adv. Civ. Eng. 2019, 2019, 2042460. [Google Scholar] [CrossRef]
- He, M.C.; Ma, X.G.; Yu, B. Analysis of Strata Behavior Process Characteristics of Gob-Side Entry Retaining with Roof Cutting and Pressure Releasing Based on Composite Roof Structure. Shock. Vib. 2019, 2019, 2380342. [Google Scholar] [CrossRef] [Green Version]
- Li, C.E.; Duan, H.M.; Wang, D.Q. The Application of High Strength Anchor about Compound Roof Support about in Guantun Coal Mine. Adv. Mater. Res. 2013, 813, 281–283. [Google Scholar] [CrossRef]
- Mandal, P.K.; Das, A.J.; Kumar, N.; Bhattacharjee, R.; Tewari, S.; Kushwaha, A. Assessment of roof convergence during driving roadways in underground coal mines by continuous miner. Int. J. Rock Mech. Min. Sci. 2018, 108, 169–178. [Google Scholar] [CrossRef]
- Sneddon, C.; Manuel, S. Use of Recycled Drill Pipes for Soldier Piles and Anchored Walls for Roadway Embankment Reconstruction. Geotech. Front. 2017, 453–460. [Google Scholar] [CrossRef]
- Kang, H.P.; Li, J.Z.; Yang, J.H.; Gao, F.Q. Investigation on the Influence of Abutment Pressure on the Stability of Rock Bolt Reinforced Roof Strata Through Physical and Numerical Modeling. Rock Mech. Rock Eng. 2017, 50, 387–401. [Google Scholar] [CrossRef]
- Coggan, J.; Gao, F.Q.; Stead, D.; Elmo, D. Numerical modelling of the effects of weak immediate roof lithology on coal mine roadway stability. Int. J. Coal Geol. 2012, 90, 100–109. [Google Scholar] [CrossRef]
Roof Type | Serial Number | Lithology | Thickness/m | Elastic Modulus/MPa | Poisson’s Ratio |
---|---|---|---|---|---|
Composite roof | 1 | Mudstone | 0.60 | 926 | 0.32 |
2 | Upper layer of | 0.26 | 445 | 0.33 | |
5# coal seam | |||||
3 | Tonsteins | 0.68 | 1635 | 0.32 | |
4 | Medium layer of | 0.20 | 445 | 0.33 | |
5# coal seam | |||||
5 | Tonsteins | 0.40 | 1938 | 0.32 | |
6 | Lower layer of | 0.22 | 445 | 0.33 | |
5# coal seam | |||||
Main roof | 7 | Pelitic siltstone | 2.09 | 4038 | 0.28 |
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. |
© 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
Share and Cite
Yu, Y.; Lu, J.; Chen, D.; Pan, Y.; Zhao, X.; Zhang, L. Study on the Stability Principle of Mechanical Structure of Roadway with Composite Roof. Minerals 2021, 11, 1003. https://doi.org/10.3390/min11091003
Yu Y, Lu J, Chen D, Pan Y, Zhao X, Zhang L. Study on the Stability Principle of Mechanical Structure of Roadway with Composite Roof. Minerals. 2021; 11(9):1003. https://doi.org/10.3390/min11091003
Chicago/Turabian StyleYu, Yang, Jianfei Lu, Dingchao Chen, Yuxin Pan, Xiangqian Zhao, and Lianying Zhang. 2021. "Study on the Stability Principle of Mechanical Structure of Roadway with Composite Roof" Minerals 11, no. 9: 1003. https://doi.org/10.3390/min11091003