The Initial Crack Formation And Application Research About The Controlled Blasting In Cutting Seam Cartridge

The technology of controlled blasting in cutting seam cartridge make full use of theenergy of explosion by explosive, effectively improve direction of explosion energy. Atpresent, we usually assue that the rock damage directly in the elastic state and simple modelon the study of controlled blasting in cutting seam cartridge. It’s still rare to study the processof controlled blasting in cutting seam cartridge useing the elastic-plastic theory.From the formation mechanism to the initiation of cracks which are caused by thetechnology of controlled blasting in cutting seam cartridge, this topic use the method ofnumerical simulation study the initiation of cracks. The finally results are as follows:(1) In this paper, we have analyzed the basic principle of controlled blasting in cuttingseam cartridge, studied the formation of initial cracks which are based on the elastic andelastic-plastic theory and put forward the initial crack propagation conditions. Through theanalysis of elastic-plastic theory, J integral can be used as the only measure of crack tip fieldstrength at the J integral leading and J integral controlling. The J integral is more suitable forthe calculation of initial crack formation about controlled blasting in cutting seam cartridge.(2) The numerical simulation software is used to establish2D and3D models about thecontrolled blasting in cutting seam cartridge. In the process, we have studied several factorsaffecting the controlled blasting in cutting seam cartridge. Analysis shows that it’s moredifficult to achieve the goal of realization of directional blasting when the coefficient of notcoupling is too large or too small. When we have the suitable coefficient of not coupling, itcan effectively form strong flow concentration and a long crack to realize the purpose oforientation fracture blasting. When the coefficient of not coupling, hole diameter and thematerial of cutting tube are determined, it can achieve the best effect under the optimal cuttingseam width values in theory.(3) Under the condition of elastic-plastic, the parameters of blasting hole charge whichcontains the per blasthole’ charge weight, line density and the minimum resistance line are introduced. Finally it establish the numerical model of controlled blasting in cutting seamcartridge about double orifice. Simulation results show that the hole spacing can be expandedunder the reasonable loading structure. Finally it make the cracks through until the rock wasbroken.