Presplitting Blasting Technology Apply In Jin Ping Hydropower Station Project

The first-degree hydropower station project of Ya Long Jiang Jin Ping in Si Chuan,the heights of the dam more than 520 meters, most of the stair reach than 30 meters, some stair reach 45 meters, in order to guarantee the stabilization of high slop and the dig quality of world no.1 high dam foundation, we adopt previous-blasting technology in this project, the construction quality of slop and spandrel slot previous-blasting is the most important thing, we deal with previous-blasting with systematic and comprehensive in theoretic and construction technical analyze, which has very important realistic significance.The paper analyzes the previous-blasting in theoretic and construction experience, it sums up the application and results of previous-blasting technology in Jin Ping hydropower station。According to the study results of home and abroad , the author analyzes the mechanism of previous-blasting produces gap,engineering rock is damage material, there are many tiny cracks in the rock, under the blasting stress wave and blasting gas produce static stress effect ion , as the result of stress plus,stress concentration and hollow hole effect, there will produce perforation crack in fired hole, stress intensity coefficient and material rupture tenacity decide the crack。We make use of the practice in Jin Ping hydropower station project, adopting engineering analogy,theoretic calculation,realistic testing,dynamic adjustive method。We can educe series of results in Jin Ping hydropower station project:1,We can fix the various blasting coefficient from theoretic facet, it is testified,optimized,adjusted in the practice,we get the blasting coefficients suit the Jin Ping hydropower station project,moreover , educing the experiment formulation of line charge density:Δ= 400a0.58。2,the experiment formulation of blasting seismic as follows:back direction v=74(Q1/3/R)1.3;side direction v=60.5(Q1/3/R)1.4。3,Previous-blasting can effectively control the foundation damage,making the sound attenuation of rocks under 1m no more than 10% in blasting fore-aft, appearance quality also can satisfy requirement。4,we can predict hole drift of the previous-crack hole,getting the curves suit the Jin Ping hydropower station project。Using lots of theoretic analyze,practice,gathering lots of basic dates , systematically,comprehensively study and summarize the previous-blasting technology in Jin Ping hydropower station project,other projects can refer it。...