Mechanism And Application Of Slotted Cartridge Smooth Blasting

The slit blasting smooth blasting technology is widely used in engineering blasting due to its advantages of simple process,convenient construction and excellent effect.After the smooth blasting of the slit cartridge,the flatness of the blasting profile is high,and the rock cracks are few,which reduces the damage of the surrounding rock during blasting.The stability of the surrounding rock is guaranteed,reducing the possibility of construction accidents.Therefore,to study the smooth blasting of the slitting cartridge and analyze its rock breaking mechanism has extremely high application value.In this paper,the numerical simulation technology is used to study the smooth blasting of the slitting cartridge.According to the principle of the controlled blasting action of the slit cartridge,the numerical calculation models of the blasting of the slit cartridge and the ordinary cartridge were established respectively,and the pressure action process after the blasting of the slit cartridge and the ordinary cartridge was compared and analyzed.It is proved that slit blasting hinders the diffusion of blasting energy in the direction of non-slotting,improves the blasting energy distribution from the aspects of pressure peak and action time,and affects the blasting effect.Aiming at controlling the blasting damage of the slitting cartridge,it is proved that there are two kinds of mechanical effects due to the existence of the slitting pipe in the slitting cartridge blasting;the compressive stress concentration in the slit direction and the compressive stress in the non-slit direction decrease.Under the joint action of the two mechanical effects,while increasing the blasting pressure in the slit direction,reducing the blasting pressure in the non-slit direction,improving the distribution of blasting pressure in the blast hole and improving the blasting effect.Regarding the structural parameters of the slitted pipe,the width of the slit is not as large as possible.There is an optimal value.After exceeding this value,the damage control effect decreases instead.The damage control effect increases with the wall thickness of the slit tube.However,there is a limit value for increasing the wall thickness.After the wall thickness exceeds the limit value,the damage control index gradually approaches a fixed value,and the improvement of the damage control effect is not obvious.For the smooth blasting of the slit cartridge,the blasting effect is affected by the spacing of the smooth blast holes.The greater the hole spacing,the less the surrounding rock damage between the holes and the worse the smooth blasting effect.However,when the hole spacing is too small,many secondary cracks will be generated on the blasting surface,which not only causes waste of blasting energy,but also affects the effect of smooth blasting.When the gap between the smooth blast holes of the slit cartridge is 10 times the blast hole diameter,apart from the two blast holes,the secondary cracks are less,the blast surface is flat,and the blast effect is the best.For the destruction of the rock mass around the hole,the surrounding rock mass is different due to the different location;the rock mass in the direction of the connection of the light burst hole is mainly tensile failure;there is only a small amount of rock in the 45 ° direction of the rock mass The body undergoes tensile failure.There is no damage to the rock body in the direction of 45° to the connection line.On the basis of theoretical analysis and numerical simulation,relying on the construction of the Baojiashan tunnel project,the smooth blasting engineering test and research of the slitting powder package were carried out,and the blasting effect was good.