Rib Spalling 3D Model for Soft Coal Seam Faces with Large Mining Height in Protective Seam Mining: Theoretical and Numerical Analyses
Fully-mechanized mining of coal face with a large cutting height is generally jeopardized by rib spalling disaster in the working face. Preventive measures based on undisturbed coal seam conditions fail to provide safe predictions, as large-scale fractures in soft coal face frequently appear before...
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| Format: | Article |
| Language: | English |
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Wiley
2020-01-01
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| Series: | Geofluids |
| Online Access: | http://dx.doi.org/10.1155/2020/8828844 |
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| author | Shuai Liu Ke Yang Tong Zhang Chunan Tang |
| author_facet | Shuai Liu Ke Yang Tong Zhang Chunan Tang |
| author_sort | Shuai Liu |
| collection | DOAJ |
| description | Fully-mechanized mining of coal face with a large cutting height is generally jeopardized by rib spalling disaster in the working face. Preventive measures based on undisturbed coal seam conditions fail to provide safe predictions, as large-scale fractures in soft coal face frequently appear before excavation due to mining-induced stresses. This paper investigates a case study of the Paner Mine 11224 working face in the Huainan mine area, China, which features an overlying protected layer in the protective seam mining. To simulate the failure process in such a mine, we elaborated a simplified physical-mechanical model of a coal wall that underwent shear failure and sliding instability, in compliance with the triangular prism unit criterion. Similar simulation experiments, theoretical calculations, and borehole monitoring were used to comprehensively analyze the overburden fracture and movement after mining the lower protective seam. The development height of three overburden zones was determined, and the characteristics of the protected layer affected by mining were obtained. The results show that the failure is mainly related to the roof load, coal cohesion, internal friction angle, coal seam inclination, and sidewall protecting force. The key to limiting the frictional sliding of a slip body is to reduce the roof load and increase the sliding coefficient and cohesion of the main control weak surface (MCWS). Besides, a self-developed three-dimensional numerical calculation software RFPA3D (Realistic Fracture Process 3D Analysis), which considered the rock heterogeneity, was used to reproduce a weak triangular prism’s progressive failure process. The numerical simulation results agreed with the fracture pattern predicted by the theoretical model, which accurately described the rib spalling mechanisms in a soft coal face with a large cutting height and a protective layer. |
| format | Article |
| id | doaj-art-b7d795a1c9114991885a94b2763a73f4 |
| institution | Kabale University |
| issn | 1468-8115 1468-8123 |
| language | English |
| publishDate | 2020-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geofluids |
| spelling | doaj-art-b7d795a1c9114991885a94b2763a73f42025-02-03T05:53:52ZengWileyGeofluids1468-81151468-81232020-01-01202010.1155/2020/88288448828844Rib Spalling 3D Model for Soft Coal Seam Faces with Large Mining Height in Protective Seam Mining: Theoretical and Numerical AnalysesShuai Liu0Ke Yang1Tong Zhang2Chunan Tang3School of Resources and Civil Engineering, Northeastern University, Shenyang 110819, ChinaInstitute of Energy, Hefei Comprehensive National Science Center, Hefei 230031, ChinaInstitute of Energy, Hefei Comprehensive National Science Center, Hefei 230031, ChinaSchool of Resources and Civil Engineering, Northeastern University, Shenyang 110819, ChinaFully-mechanized mining of coal face with a large cutting height is generally jeopardized by rib spalling disaster in the working face. Preventive measures based on undisturbed coal seam conditions fail to provide safe predictions, as large-scale fractures in soft coal face frequently appear before excavation due to mining-induced stresses. This paper investigates a case study of the Paner Mine 11224 working face in the Huainan mine area, China, which features an overlying protected layer in the protective seam mining. To simulate the failure process in such a mine, we elaborated a simplified physical-mechanical model of a coal wall that underwent shear failure and sliding instability, in compliance with the triangular prism unit criterion. Similar simulation experiments, theoretical calculations, and borehole monitoring were used to comprehensively analyze the overburden fracture and movement after mining the lower protective seam. The development height of three overburden zones was determined, and the characteristics of the protected layer affected by mining were obtained. The results show that the failure is mainly related to the roof load, coal cohesion, internal friction angle, coal seam inclination, and sidewall protecting force. The key to limiting the frictional sliding of a slip body is to reduce the roof load and increase the sliding coefficient and cohesion of the main control weak surface (MCWS). Besides, a self-developed three-dimensional numerical calculation software RFPA3D (Realistic Fracture Process 3D Analysis), which considered the rock heterogeneity, was used to reproduce a weak triangular prism’s progressive failure process. The numerical simulation results agreed with the fracture pattern predicted by the theoretical model, which accurately described the rib spalling mechanisms in a soft coal face with a large cutting height and a protective layer.http://dx.doi.org/10.1155/2020/8828844 |
| spellingShingle | Shuai Liu Ke Yang Tong Zhang Chunan Tang Rib Spalling 3D Model for Soft Coal Seam Faces with Large Mining Height in Protective Seam Mining: Theoretical and Numerical Analyses Geofluids |
| title | Rib Spalling 3D Model for Soft Coal Seam Faces with Large Mining Height in Protective Seam Mining: Theoretical and Numerical Analyses |
| title_full | Rib Spalling 3D Model for Soft Coal Seam Faces with Large Mining Height in Protective Seam Mining: Theoretical and Numerical Analyses |
| title_fullStr | Rib Spalling 3D Model for Soft Coal Seam Faces with Large Mining Height in Protective Seam Mining: Theoretical and Numerical Analyses |
| title_full_unstemmed | Rib Spalling 3D Model for Soft Coal Seam Faces with Large Mining Height in Protective Seam Mining: Theoretical and Numerical Analyses |
| title_short | Rib Spalling 3D Model for Soft Coal Seam Faces with Large Mining Height in Protective Seam Mining: Theoretical and Numerical Analyses |
| title_sort | rib spalling 3d model for soft coal seam faces with large mining height in protective seam mining theoretical and numerical analyses |
| url | http://dx.doi.org/10.1155/2020/8828844 |
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