The Technology Study Of Controlled Fracture For Borehole

With the past theories and practices of fracture controlled blasting, on the basis of the in being explosive theories and technology, a new method of fracture blasting-use different coupling medium-water and gas within the hole at the same time is put forward in this paper, mostly making use of the different physics and transmitted energy characteristic of water and gas.The method includes the characteristic of hydraulic pressure blasting and gas decoupling blasting. The paper studies the cracking mechanism of directional broken control blasting by fracture mechanism. Using the broken damage theory, the paper also analyses the damage after blasting, establishes the reference of beginning, widening and ceasing of crack caused in the process of blasting, obtains their main parameters and formula.The paper studies the spreading of shock wave and its effects in the hydraulic pressure blasting and gas decoupling blasting in detail. It also introduce the causing of shock wave in the water and the gas, and its spread in blasting hole, as well as its reflection and transmission and effects of rock.By theory studied and model test, the paper analyses thedestructive characteristic and effects of this method. In contrast with the strain and damage at the direction of the water and the gas after blasting, suffering force and distortion were reflected. It validate the theory and make out the feasibility about the method. The blasting method can control energy releasing and direction effectively, more control rupture direction, which makes it possible to destroy one side of the wall rock and at the same time protect the other side.In brief, the new blasting method is an convenient and effective controlled fracture blasting method. It not only can controls the creating and extending of the cracking, but also can decreases vibration, protects rock stabilization, reduces powder and noise. It has great value of spreading usage.