Mechanical model and numerical analysis of a method for local rock reinforcing to control the floor heave of mining-affected roadway in a coal mine

Abstract

A floor heave controlling method has been substantiated, based on the creation of locally reinforced zones of a special shape in roadway floor, which allows saving stability even with a low rocks friction ratio. The method is based on a mechanical model of the formation of an increasing strength spacer system in roadway floor. The numerical analysis of rock massif stress-strain state carried out by the finite element method, has made it possible to determine the mechanism of floor heave during rock reinforcing. The performed analysis of the simulation results has made it possible to determine the influence of the quality of rock reinforcing and the rock friction ratio value on the amount of heave in the mining-affected roadway. The effectiveness of the proposed method has been proven as a result of a comparative analysis.

Numerical Modeling of Controlling a Floor Heave of Coal Mine Roadways with a Method of Reinforcing in Wet Soft Rock

“…The conducted studies confirm the well-known phenomenon observed onsite, that in the zones of water inflows, the swelling of the floor becomes more active and can exceed 1/3 of the height of the roadway [5][6][7]42]. At the same time, the values of the floor heave in such conditions exceed those ones in dry rocks by 3-4 times.…”

“…The fractional analysis of rocks, carried out by the authors at different coal mines in places of excavation of rock by a dramatic floor heave, enabled us to draw a conclusion that rocks in the fracture zone are mainly represented by a block discrete environment [7]. Under such conditions, a floor heave mechanism is most likely to occur due to the squeezing out of fractured rocks located within the fracture zone into the opening cavity, caused by the growth of a nonelastic zone around the roadway.…”

“…A floor heave in the mine roadway while extracting coal can exceed 1 meter, especially in conditions of increased water inflows [5][6][7]. This causes problems with the transport of loads and minerals and the supply of air through the mine roadways and also leads to the risk of injuring miners while they are moving along the mine roadways.…”

“…Zhang et al and Shimada [22] explored the evolution of stress at the floor of roadways by FLAC3D. Sakhno et al [7] performed numerical modeling of controlling a floor heave of roadways in wet soft rock by Ansys. Małkowski et al [24] proposed the new modeling methodology for roadway floor heave on the base of numerical simulation by Phase 2.…”

Numerical Studies of Floor Heave Control in Deep Mining Roadways with Soft Rocks by the Rock Bolts Reinforcement Technology

“…Qi et al [3], and Zhang et al [28] simulated the failure mechanism of soft rock roadway by UDEC. Sakhno et al [29] performed numerical modelling of controlling a foor heave of roadways in the soft rock by ANSYS. Małkowski et al [26] used a phase 2 program.…”