Abstract
The segment lining is a new type of support structure for mining tunnels. The disturbance of coal excavation leads to the deformation of segment lining and has great hazards to the safety of the tunnels. Based on the tunnel boring machine (TBM) inclined tunnels in Xinjie mine, the ultimate span L0 of the rock beam on the top slab of the coal seam was calculated according to the bending (tension) damage theory. A numerical model was built to simulate the bottom area of the inclined tunnels. During the coal mining, the additional displacements and additional stresses of the segment lining were analyzed, and then the safety factors of the support structure were calculated. Finally, the width of the coal pillar to protect the inclined tunnels was determined. The results showed that the ultimate span of the rock beam on the top of the coal seam is 31.7 m, the deformation of the inclined tunnel has a fish-belly shape, and the deformation leads to the increase of maximum axial force and bending moment. For the inclined tunnels in Xinjie coalmine, a total width of 91.3 m of coal pillar must be reserved to keep the safety factor of the structure higher than 2.0 and prevent the inclined tunnels from the mining hazards.
Highlights
The tunnel boring machine (TBM) has been widely used to build transportation and hydraulic tunnels, but its application in mining engineering is still limited (Liu et al, 2013)
The segment lining is a new type of support structure for mine tunnels
It was proposed that the coal pillar with reasonable width must be reserved to prevent the tunnels from mining hazards
Summary
The tunnel boring machine (TBM) has been widely used to build transportation and hydraulic tunnels, but its application in mining engineering is still limited (Liu et al, 2013). In the coal excavation process, the roof rock beam changes from the fixed beam to the supported beam, and the bending moment transfers from the two ends to the middle (Huang, 2002). Based on the geological survey data of Xinjie coalmine, the overlying ground pressure of the coal seam is 14.4 MPa, and the coal roof is fine-grained sandstone with a thickness of 10 m, density of 2.47 × 103 kg/m3, and tensile strength of 1.24 MPa. According to Eq (Shi et al, 2017), the ultimate span of the rock beam can be obtained as L0 31.7 m. For concrete segment lining structures, the safety factor could be calculated based on the maximum compressive stress in the compressed area and the design strength of concrete material (Vogel et al, 2000). The theoretical calculation results have high consistency with the numerical simulation, and the error is within a reasonable range, so it shows that the numerical simulation results are accurate and valid
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
