Abstract：A new cutting method named quasi-parallel cutting method is proposed according to the rock blasting theory；and it helps to achieve the goal of rapid drivage for rock roadway by drilling and blasting and to overcome the deficiencies in parallel cutting and inclined-hole cutting. Quasi-parallel cutting method is a break through to the traditional cut blasting design. Main cutting holes(quasi-parallel holes) are slightly inclined；their distances at the bottom are long；and sub-cutting holes are perpendicular to the free face. Compared with current cutting methods，it has the following advantages：(1) It avoids the phenomenon of drilling holes crossing each other because of long distance at the bottom of quasi-parallel holes. (2) Slicing and stage blasting method is used at a reasonable interval time. (3) Straight sub-holes in the center and the symmetrical quasi-parallel holes cooperate with each other；it is a successful combination of parallel cutting method and inclined-hole cutting method. (4) The cutting form is very simple and easy to operate. (5) It can get large cavity with high efficiency and low-cost. Based on the quasi-static theory of blasting gas and the limit equilibrium theory of rock mechanics，the generation process of cavity has been analyzed. For the purpose of optimizing the quasi-parallel cutting parameters，a series of field tests are carried out；technical parameters of cutting holes including layout，depth，angle of inclination，spacing，charge and the interval time of short-delay blasting are obtained under different blasting conditions. Angle of quasi-parallel hole is determined by measuring length during construction，which can meet its accurate requirements. The test results show that the better blasting effect and obvious technical and economic benefits in coal rock drivage can be acquired by means of the quasi-parallel cutting method.
2011, Vol. 30 
