Difference in rock-breaking characteristics between water-coupling blasting and air-coupling blasting

The water-coupling blasting (WCB) technology has received widespread attention due to its advantages of high efficiency and environmental protection. However, the parameters of WCB in practical engineering are generally determined based on the experience and standards of air-coupling blasting (ACB), leading to poor blasting effects and wastage of explosive energy. The study focuses on comparing the rock-breaking effects of shock waves and explosive gases between WCB and ACB to offer insights for optimizing the design of WCB. Firstly, the stress field in blasting with different coupling mediums was calculated. Then, the shock failure characteristics of rocks between WCB and ACB were analyzed. The results show that the radius of shock failure zones decreases with the increasing decoupling coefficient in WCB and ACB. On this basis, a model for calculating the shock failure range in WCB and ACB was proposed. This model can be utilized to estimate the percentage of fine-grained stone in the two types of blasting. Further, a method for distinguishing between the rock-breaking effects of shock waves and explosive gases was proposed based on the numerical simulation results of blasting damage. A comparative analysis between WCB and ACB on the rock-breaking volume by shock waves and gases was conducted. The results indicate that the failure volumes of rocks induced by shock waves and gases in WCB are 1.4-2.1 times greater than those in ACB, with a decoupling coefficient ranging from 1.26 to 1.71. Finally, a method for determining the charging structure in WCB was discussed, which has been preliminarily validated by field tests. The findings can help regulate rock-breaking effects in blasting by rationally selecting coupling mediums and charging constructions.