Failure Characteristics of the Water-Resisting Coal Pillar under Stress-Seepage Coupling and Determination of Reasonable Coal Pillar Width

Groundwater inrush hazard has always been a great threat to the construction of vertical shafts in coal mines. Generally, failure water-resisting pillar under coupled stress-seepage conditions around shaft is main reason for generation water channel. In order understand mechanical behaviors pillar, strength typical affected by size and content was investigated, stress sensitivity permeability investigated coupling test. The field deformation were numerical simulation, stability pillars with different widths evaluated, reasonable width condition determined. Results show that have influence on characteristics samples. Under lower larger sample width, presents higher strength, smaller axial deformation, porosity, weak stress. simulation results boundary roadway at end dominated tensile stress, fractures can significantly contribute destruction pillars. With increase internal damage variable, maximum average flow velocity decrease, which reduces risk improves safety pillar. An evaluation model proposed, verified shear slip law experimental results. This study provides theoretical guidance management groundwater disaster during