多台阶地形爆破动力响应分析及安全振速判定

Dynamic Response Analysis on Multi-level Terrain Blasting and Safety Vibration Velocity Determination

以三友矿山露天边坡为研究对象,通过数值模拟的方法,通过分析得出结论:在爆破近区,振速衰减较大,但随着高程的增加,高程放大作用呈现先增大后减小的趋势,并且在坡顶有一定的反射放大作用;目前表征高程放大效应的爆破振速预测公式在爆破震动传播方向与台阶坡面垂直的情况下较为准确。但是,当高程不变,爆心距沿台阶坡面不断增大时,其公式的准确性大幅下降;建立了剪切应力峰值与合速度峰值之间的线性关系,计算出台阶的安全振速极限值为12.17cm/s。

Taking Sanyou open pit slope as the research object, numerical simulation was carried out to obtain results as follows. Firstly, in the near blasting area, the attenuation of velocity was large. But with increasing the elevation, elevation amplification showed the tendency, increased at the beginning and then decreased. At the same time, there was some reflection amplification phenomenon in the top of the slope. Secondly, the prediction formula of blasting vibration velocity, which reflected the elevation amplification effect, was relatively accurate in case blasting vibration propagation direction was perpendicular to the slope of the step. However, when the elevation was changeless and blasting distance increased continuously along the bench slope, the accuracy of the formula dramatically dropped. Thirdly, a linear relationship between shear stress peak and velocity peak was established, and the limit value of safety vibration velocity for the slope was calculated as 12.17 cm/s.