A study of innovative cut blasting for rock roadway excavation based on numerical simulation and field tests

Drilling and blasting is a common excavation method in underground engineering. In modern mine construction, improving the efficiency of rock roadway excavation is a significant issue. With the development of blasting practices and the deepening technical understanding, it is difficult to implement deep-hole blasting with traditional drilling and blasting. The reason is that conventional cut blasting makes it difficult to fully throw out rock masses and create enough free surface. In this paper, an innovative cut blasting technology based on cavity cutting and fragment throwing (CCFT) is studied. It overcomes the limitation of dense hole layout, but strengthens the charge at the bottom, and forms a more sufficient cut cavity through a two-stage explosion. Based on the above ideas, a parallel cut with a double fragment-throwing hole (P-DFH) was designed for the excavation of rock roadways. The effects of CCFT cut blasting were studied at the mesoscopic and macroscopic levels. The smoothed particle hydrodynamics-finite element method (SPH-FEM) was used to establish a P-DFH model. The mechanism of cut cavity formation was studied. The arbitrary Lagrange-Euler with erosion algorithm (ALEEROSION) was used to establish a global geological model for roadway excavation, and the evolution of rock failure in stages was analyzed. Finally, a field test was conducted to verify the effectiveness of the CCFT technique through monitoring. The application of the CCFT technique has achieved significant results for improving face advance, protecting surrounding rock, and controlling blasting vibration.