SPALLING AND CUTTING MECHANISM OF HARD NODULES IN THIN COAL SEAM

摘要

Aiming at the problem of drum shearer breaking coal on the thin coal seam with hard nodules, we have studied the form and mechanism of the overall spalling and direct cutting of thin coal seam face nodules by the means of theoretical analysis and numerical simulation. Research shows that when shearer picks cut the nodules, compressive-shear and tensile rupture will happen in the inclusion of nodules on the back, and develop into plastic compaction nuclear. And then the rupture will expand along the inclusions to form through-type rupture with the overall spalling occurring after nodules deflection. If the nodules and parting are relatively thin, there will be a "θ" form rupture zone in nodules and inclusion, and then we can directly cut the nodules. How the nodules spall depends on the size of nodules as well as the strength of inclusion. Sometimes there will also be the form of spalling after cutting.