By researching both the thickness deformation law of the ring with stepped cross sections rolled from the ring with rectangular cross sections and the shrinking-drawing between active and passive deforming parts of the ring, a new concept of compound shrinking-drawing coefficient is proposed and its calculation formula and scope of numeral value .

Based on comprehensiveness analysis and calculation on data from blasting experiments including blasting crater, incline bench, different distance of hole,initiation in multi-row and same stage, optimization of blasting parameters such as distance of hole bottom, minimum burden, explosive consumption an unit etc.