炭鉱のガス突出防止のためのスリットを用いた応力解放に関する模型実験

Abstract

Stress relief method is widely used in coal mines in many countries to prevent the gas outburst and rock burst. It is one of the effective methods of relieving the stress to cut the slits in coal seams.The author made a model experiment to investigate the effect of the slitting at the heading face on the stress relief. A three-dimensional model experimental apparatus of about 1: 80 geometrical scale was used. The dependence of slit thickness, number of slits and the strength of model coal seam on the effect of the stress relief was measured. As the model rock mass, the gypsum plate was used and as the model coal seam, an artificial seam made from the mixture of water, gypsum and diatomite was used. The scale factor of the stress and strength was 1: 40.The effect of the stress relief was evaluated by the degree of stress relief defined by the author. A slitting standard for effective stress relief, such as to cut the several parallel slits and to cut the slits near roof or floor, was proposed.