Experimental investigation of borehole blasting with eco friendly rapid setting gun mud.

To address the challenges of inconvenient material sourcing and low stemming efficiency in horizontal tunnel blasting, this study proposes a novel rapid-setting gun mud. The material's composition, formation mechanism, and initial setting characteristics are first analyzed, and a multi-parameter coupled model for optimal stemming length is established. Subsequently, a series of blasting model tests with varying stemming lengths is conducted, followed by a quantitative analysis of the block-size distribution of limestone under different stemming conditions. The influence of stemming length on rock fragmentation characteristics is revealed, and theoretical predictions are validated against experimental results. Findings indicate that the curing process of the proposed material is primarily driven by hydration reactions, with simple operation, environmental friendliness, and safety for workers. Moreover, the developed multi-parameter coupled model for optimal stemming length shows good agreement with experimental results, providing a quantifiable theoretical basis for the refined parameter design in mechanized tunnel blasting.