The Theory and Practice of Advance Blasting in Frozen Basement Rock of Vertical Shaft

摘要

This paper first analyses and researches advance blasting mechanism and parameters design in frozen basement rock of vertical shaft from theory, then applies to engineering practice. The results show: Using hole blasting in frozen basement rock of shaft is completely feasible, it can Improve tunneling speed to a greatest extent and decrease operation labor intensity. Shallow hole of hole multi circles are fit in drilling and blasting in frozen soil of vertical shaft, depth of hole L_b = 1.2 ～1.4m; Shatter cylindrical cut, perimeter smooth blasting; The more rational cut parameters are: arranging circle diameter of slot hole D = 1.0 ～ 1.2m, hole spacing a = 500 ～ 700mm, powder factor q = 2.2 ～ 2.8kg/m~3; The more rational smooth-blasting parameters are: side holes spacing E = 500 ～ 600, thickness of smooth-blasting layer W = 600 ～750mm, concentration coefficient of holes m = 0.8 ～ 1.2, charge concentrated density q_L = 150 ～ 250g/m, air cushion loaded constitution.