Experimental Study On Crack Propagation Of Grooving Grain

Rock blasting technology has been used more and more widely in modern engineering.But the traditional blasting method is not easy to control,low efficiency and lack of safety.Directional blasting can precisely control the formation,extension,development direction and formation of rock fracture surface.In order to directional blasting fracture capacity of different charge structures groove of the grain,the grain,the groove design of transverse grooved column and vertical double slit groove column three forms column vertical slit,carry out mortar blasting model test on three kinds of grain.Coring,slicing through the three kinds of groove propellant after explosion model,obtained the crack distribution form section specimens at different locations on the model,according to the blasting side and the back side of the explosion crack geometry,analysis of a groove form has the most effect on the rock directional fracture blasting.At the same time,buried resistance strain gauge in vivo model of pre blasting process model of explosion stress wave test,according to the different position of the strain gauge measured values of wave stress,further analysis of the mechanism of directional fracture blasting.In order to directional blasting fracture capacity of different charge structures groove of the grain,the grain,the groove design of transverse grooved column and vertical double slit groove column three forms column vertical slit,carry out mortar blasting model test on three kinds of grain.Coring,slicing through the three kinds of groove propellant after explosion model,obtained the crack distribution form section specimens at different locations on the model,according to the blasting side and the back side of the explosion crack geometry,analysis of a groove form has the most effect on the rock directional fracture blasting.At the same time,buried resistance strain gauge in vivo model of pre blasting process model of explosion stress wave test,according to the different position of the strain gauge measured values of wave stress,further analysis of the mechanism of directional fracture blasting.The main conclusions are as follows:In the three kinds of charge groove,the single slot groove in the groove of three kinds of groove has the best effect on the directional fracture of the model.Remove the punch hole blasting effect of bias on the part of the model test in the vertical groove of grain,try to crack on the formation of clear rules and crack crack attack blasting side than the back blast side is more obvious,the length is also increased.The formed cracks.are also concentrated,and the single concentrated cracks are formed in all directions.The effect of crack formed by transverse grooving of grain to a lot of difference in directional blasting,not only the formation model of regional crack is smaller,do not focus on the crack distribution,the blast side does not have any advantage at all,not suitable for application in directional fracture blasting.For vertical slotted slot columns,there is almost no observable crack trace in the model,and the effect is not obvious.The strain sheet value of the vertical single slot groove model is larger than that of the back blasting at the same height.The three strain gauges on the explosion side,the middle position of No.two is the largest,and the upper part is the least.By comparing the measured values of the strain gauges with the slice crack distribution in the test,the superiority of the vertical single slit groove in the directional fracture blasting of rocks is further verified.