METHOD OF FORMATION OF TRENCHES BY BLAST Russian patent published in 1996 - IPC

FIELD: construction industry. SUBSTANCE: invention refers to formation of trenches, canals and so on in hard rocks and frozen soils. Slits are cut along contour and in contour of formed trench. Linear explosive charges distributed by tamping over height are placed into slits in contour of trench along their length. Charges are blasted, loosened mass is removed. Charge slits are cut to depth H₃ equal to sun of design depth of positioning of axis of pipe-line, radius R of pipe-line, thickness t of soft cushion on bottom of trench and value C equal to , where α is permissible inclination angle of bottom of blast depression and its symmetry axis in cross-section (90^°<α≥45^°), k is coefficient determined by number n of charge slits with n=1, k=1, with n > 1, k=0. Compensating slits over contour of depression are cut to depth H_k= H₃-lctgα, where 1 is distance between nearest charge and compensating slits. EFFECT: enhanced efficiency of trench formation. 4 dwg