中深孔爆破块度控制的最佳不耦合系数试验研究

Experimental Study on the Optimum Decoupling Coefficient for Controlling Block Size of Medium and Deep Hole Blasting

分析了中深孔台阶爆破装药不耦合系数的选取方法。结合上海洋山港区工程爆破及抛填项目进行小台阶模型试验,研究不耦合系数对块度的影响情况。小台阶模型试验几何常数取为10,试验选取单排孔形式进行,分别选取 1. 0、1. 25、1. 50、1. 75、2. 0等5种不耦合系数,共完成10次模型试验。对每次试验爆后岩块粒度大小分布筛分统计,将爆后岩体块度统计数据进行相关线性回归处理,得出均匀指数、特征块度、相关系数、K50等四项爆破块度评价指标随不耦合系数的变化关系。结果表明,用不耦合装药可以大大改善爆破的块度指标,且有最佳不耦合系数。上述工程二期大指头岛爆破现场,其最佳径向不耦合系数为 1. 5~1. 75。

The selection method of decoupling coefficient of charge in medium and deep hole bench blasting is analyzed. A small bench model test was carried out to study the influence of decoupling coefficient on fragmentation in combination with blasting and landfill projects in Shanghai Yangshan port area. The geometric constants of the small bench model test are 10,and the single row holes are selected for the test. Five decoupling coefficients,1. 0, 1. 25,1. 50,1. 75 and 2. 0,are selected respectively,and 10 model tests are completed. The size distribution of rock block after each test blasting is screened and counted. The statistical data of rock fragmentation after blasting are processed by correlation linear regression,and the relationship between the four evaluation indexes of blasting fragmentation such as uniformity index,characteristic fragmentation,correlation coefficient and K50 and decoupling coefficients is obtained. The results show that the fragmentation index of blasting can be greatly improved by using decoupling charge,and there exists an optimum decoupling coefficient. In the second stage blasting of Dazhitou island,the optimum radial decoupling coefficient is 1. 5 ~ 1. 75.