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单自由面爆破条件下作用在岩体上的最有效破坏力小,而阻碍岩体破坏的作用力很大,使炮孔堵塞长度对爆破振动有较大影响。因此,研究单自由面爆破振动特征的炮孔堵塞长度效应有重要意义。进行了小规模的不同堵塞长度的单自由面爆破试验,并模拟了其爆破过程。研究表明,近距范围内爆破振动速度迅速衰减,中远距离爆破振动速度衰减趋缓;随着堵塞长度的增加,场地系数K不断增加,衰减指数α总体呈上升趋势;数值模拟振动速度值与实测值误差在15%以内;爆破后不同堵塞长度模型的堵塞物底部空腔半径基本相等,约为装药半径的3倍;试验最优堵塞长度为15～20 cm,相同条件下无堵塞爆破对孔口有效应力场影响较大、对孔底有效应力场影响较小。
Under the condition of single free surface blasting, the most effective destructive force acting on the rock mass is small, while the force impeding the failure of the rock mass is very large, so that the length of the blast hole plugging has a greater impact on the blasting vibration. Therefore, it is of great importance to study the effect of blasting length on the blasting vibration of free-space surface. A small scale single free surface blasting test with different length of plug was carried out and the blasting process was simulated. The results show that the blasting vibration velocity decays rapidly in the short range and the vibration velocity attenuates slowly in the middle and long distance. As the length of the plugging increases, the coefficient K of the site increases and the attenuation index α generally increases. The numerical simulation of the vibration velocity and the measured The error of the value is less than 15%. The cavity radius of the plug at the different length of plugging model after blasting is about the same, which is about 3 times of the radius of the charge. The optimal plug length is 15 ~ 20 cm and under the same conditions, The effective stress field of the orifice is greatly influenced, but the effective stress field of the hole bottom is less affected.