River-ice blasting and explosive weight optimization for ice-flooding mitigation: A case study

Abstract Ice blasting with explosives before the spring breakup of river sections is a preventive measure for ice flooding. Based on 496 datasets on ice cover blasting with No. 2 emulsion rock explosives measured in the Mohe reach of the Heilongjiang River from 2015 to 2018, we analyzed the relationships between the blasting-crater diameter and water depth below the ice and between the blasting-crater diameter and the explosive-placement depth below the ice. Further, we analyzed the functional relationship between the explosive weight of a single blast hole and the blasting-crater diameter. Based on the above analysis we proposed an equation to calculate the minimum blasting cost for the same blasting effect. Using a 5-km section of the Heilongjiang River as an example, the proposed optimization method can save ~46% of the total blasting cost while achieving the same blasting effect. Through prototype observations of the Longdao Wharf and the Shengdan Village sections of the Mohe reach, Heilongjiang River, we confirmed that ice blasting can significantly accelerate the melting of ice. Moreover, data records showed that no significant ice-jam flooding has occurred in this section of the Heilongjiang River during the spring ice breakup period in the past five years of consecutive blasting.