Study on deformation and destruction course of coal body under function of pick cutting with digital speckle correlation method

Based on the cutting experiments used by cutter tooth and point-attack pick on the press and cutting simulation test table,the deformation and failure process of coal body are studied by the method of white light digital speckle correlation.The results indicate that a stable deformation localization band occurs in the coal cutting course and develops to macroscopic crack;the deformation localization band is slantwise;while the cutter tooth is used,the deformation localization develops slowly,and the localization becomes wider and the strain value in the band area higher afterwards;when the point-attack pick used the localization develops quickly and the localization band becomes narrow and the strain value in the band lower.Finally,the authors draw a conclusion that the main failure of coal body is shear failure under the action of cutting.