Based on cutting principle and technology development of vertical blasthole cutby stage and deck in vertical shaft excavation, combined with the merits of middle spacecharging and toe space charging, the reinforced cu...Based on cutting principle and technology development of vertical blasthole cutby stage and deck in vertical shaft excavation, combined with the merits of middle spacecharging and toe space charging, the reinforced cutting effect of central large-diameterblasthole and the method of cutting blast by stage and deck toe space charging for thevertical large-diameter blastholes was put forward and analyzed theoretically.This new cutblasting method is provided with the advantages of high blasthole using ratio, big cavitybulk, low rate of chunk, even lumpiness, and relatively high energy using ratio.The parameterchoices and practical effects of this cutting method were discussed after in situexperiment.It shows that the decked delay time of 75～100 ms is applicable.展开更多
This paper aims at reporting the results of a number of drag pick cutting tests on selected igneous rock samples to compare the experimentally determined maximum cutting force （FC） values with theoreti- cally estima...This paper aims at reporting the results of a number of drag pick cutting tests on selected igneous rock samples to compare the experimentally determined maximum cutting force （FC） values with theoreti- cally estimated ones. First, a review on theoretical rock cutting models proposed for both chisel and conical picks was presented in detail. Experimental study consists of both chisel and conical pick cutting tests in unrelieved （single-pick） cutting mode with varying cutting depths. FC＇ values were determined from experimental results, and theoretical models were utilized to compute FC for all cutting conditions. Computed and experimentally determined F（ data were then compared for a referenced cutting depth. It is shown that the theoretical models might overestimate or underestimate FC＇ and cannot give reliable results. Finally, explanations for these mismatches were presented.展开更多
基金Supported by the National Natural Science Foundation of China(50764001)Ministry of Education"Chunhui Program",Guizhou Outstanding Young Talents Foundation(200705)Scientific and Technological Tack-ling Project of Guizhou Province(20073015)
文摘Based on cutting principle and technology development of vertical blasthole cutby stage and deck in vertical shaft excavation, combined with the merits of middle spacecharging and toe space charging, the reinforced cutting effect of central large-diameterblasthole and the method of cutting blast by stage and deck toe space charging for thevertical large-diameter blastholes was put forward and analyzed theoretically.This new cutblasting method is provided with the advantages of high blasthole using ratio, big cavitybulk, low rate of chunk, even lumpiness, and relatively high energy using ratio.The parameterchoices and practical effects of this cutting method were discussed after in situexperiment.It shows that the decked delay time of 75～100 ms is applicable.
文摘This paper aims at reporting the results of a number of drag pick cutting tests on selected igneous rock samples to compare the experimentally determined maximum cutting force （FC） values with theoreti- cally estimated ones. First, a review on theoretical rock cutting models proposed for both chisel and conical picks was presented in detail. Experimental study consists of both chisel and conical pick cutting tests in unrelieved （single-pick） cutting mode with varying cutting depths. FC＇ values were determined from experimental results, and theoretical models were utilized to compute FC for all cutting conditions. Computed and experimentally determined F（ data were then compared for a referenced cutting depth. It is shown that the theoretical models might overestimate or underestimate FC＇ and cannot give reliable results. Finally, explanations for these mismatches were presented.
