Fluid-Solid Coupling Analysis Of The Safety Of The Waterproof Coal Pillar

The waterproof coal pillar may be regarded as an underground structure under the action of the overburden load and unilateral hydraulic pressure, also is one kind of distortable porous mediums that contains large amount of fissure and pores, which makes the mine water permeate into certain depth of it. Under the action of the pore water pressure, the strength and the deformation nature of the coal pillar will change with time. Even if the overburden load and the unilateral hydraulic pressure are invariable, the seepage region and the deformation of the coal pillar will vary with time. When the condition is suitable, the coal pillar will be suddenly destroyed and the water will inrush into the lower region of the mine. Therefore, the collapsing and water-inrush in coal pillar concerns not only caused by the overburden coal rock, but is a fluid-solid coupling question, which was not taken into consideration in the former design of the waterproof coal pillar.The domestic and foreign status quo of the waterproof coal pillar, fluid-solid coupling and its project practices are summarized. Then based upon the seepage theory and the finite difference, a fluid-solid numerical simulation is carried through FLAC^3D on the remaining security coal pillar in a certain colliery to analyze the stability and anti-water-inrush ability of the waterproof coal pillar. Also a comparison of the plastic status of the coal pillar is made respectively considering uncoupled and coupled situations, and the deformation and failure laws are researched. It is indicated by the numerical simulation results that the plastic zones are both like a saddle, which tallies with the former surveys; The length of the waterproof coal pillar considering fluid-solid coupling is long compare to that of the uncoupled computation, which indicates that it is necessary to consider the fluid-solid coupling in the design of waterproof coal pillar.