Amirkabir Journal of Civil Engineering

Amirkabir Journal of Civil Engineering

Numerical Modeling and Stability Assessment of the H16 Bifurcation in the Tabas Coal Mine

Document Type : Research Article

Author
Department of Mining Engineering, Amirkabir University of Technology, Tehran, Iran
Abstract
The design of tunnel networks in underground mines is inherently complex, inevitably leading to various branches and intersections. The stability of these intersections directly affects the safety and efficiency of the mine. In the present study, one of the bifurcated intersections of the Parvadeh Tabas coal mine (the H16 two branch intersection) has been investigated. The finite difference method was employed to calculate three components: the distribution of induced stresses, the stress concentration, and the extent of the plastic zone. The results show that the maximum vertical induced stress in the area between the two tunnels reaches 25.5 MPa on the left side of the intersection. In the same zone (left side of the intersection), the stress concentration increases to 1.6 near the inclined tunnel and to 1.7 near the access tunnel. At the roof of the access tunnel, moving away from the intersection is accompanied by a gradual increase in stress – a phenomenon attributed to the non circular and wide cross section of this tunnel. The modeling error in the three investigated sections was calculated based on the maximum displacements of 419, 412, and 370 mm, respectively, The relative error of the model compared to the field data was estimated at 5%, 3%, and 8%, respectively. the extension of the plastic zone at various distances from the intersection exhibits an asymmetric behavior. Furthermore, the presence of coal at tunnel floor not only intensifies the extent of the plastic zone but also directly leads to floor instability and heave.
Keywords
Subjects

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