基于准岩体抗拉强度的爆破振动速度衰减公式改进

萨道夫斯基公式在爆破中近区对质点振动速度的预测精度较低,使用该公式所得的预测误差可达200%~300%,不利于对爆破中近区的振动速度进行精确预测。爆破中近区压缩应力波拉伸破坏所造成的岩石片落和径向裂隙扩展现象比较明显,该类拉伸破坏现象在一定程度上加快了爆破振动速度的衰减过程。为研究爆破中近区岩体抗拉强度对爆破振动速度衰减的影响,在对国内外爆破振动速度衰减公式进行梳理分析的基础上,讨论了14个爆破振动峰值速度的影响因素,选取其中9个主要因素进行了量纲分析,将准岩体抗拉强度考虑在内,推导了基于准岩体强度的爆破振动速度衰减改进公式。结合某露天铁矿工程实例,采用1st0pt软件分别对改进公式和萨道夫斯基公式进行了多元非线性回归分析。研究表明:基于准岩体抗拉强度改进的衰减公式对该矿南、北区测点振动速度预测的平均相对误差分别为8.41%和7.01%,均高于传统衰减公式的预测精度,说明考虑准岩体抗拉强度对萨道夫斯基公式进行改进具有可行性,可为露天矿山爆破作业提供参考。

Improvement of the Attenuation Formula of Blasting Vibration Velocity Based on Quasi-rock Mass Tensile Strength

The predicted error of the particle blasting vibration velocity by using Sadovsky formula can be up to 200%~300% in medium or near blasting zone，which is not conducive to the accurate prediction of the blasting vibration velocity in medium or near blasting zone.The phenomenon of the rock fall and radial crack propagation caused by the tensile failure of the near-zone compression stress wave in the blasting is more obvious，and these tensile failure phenomena accelerate the decay process of the blasting vibration speed to a certain extent.In order to study the influence of rock mass tensile strength to the attenuation of blasting vibration velocity in medium or near blasting zone，based on the analysis of the existing attenuation formulas of blasting vibration velocity both at home and abroad，14 influence factors of peak blasting vibration velocity are discussed，and dimensional analysis are conducted by selecting 9 main factors of them.By considering the tensile strength of quasi-rock mass，the improved blasting vibration velocity attenuation formula is derived.Based on the engineering example of an open-pit iron mine，by using 1st0pt software，multivariate nonlinear regression analysis for the improved attenuation formula and Sadovsky formula are done respectively.The study results show that the average relative prediction error of the particle blasting vibration velocity based on the improved attenuation formula is 8.41% and 7.01% of the south and north area of the mining area，which are higher than the ones of the traditional attenuation formula.The improved attenuation formula can provide the reliable reference for the blasting operation of open-pit mine.