Eccentric decoupled charge(EDC)blasting is a widely used technique for rock fragmentation and tunnel excavation,yet the underlying rock damage mechanisms,particularly in relation to in-situ stresses and multi-borehole...Eccentric decoupled charge(EDC)blasting is a widely used technique for rock fragmentation and tunnel excavation,yet the underlying rock damage mechanisms,particularly in relation to in-situ stresses and multi-borehole combinations,remain underexplored.First,we developed an analytical model for single-borehole EDC blasting,providing insights into the theoretical relationship between the formation of different rock damage zones around the borehole and various influencing factors,including decoupling coefficient,in-situ stress,rock and explosive properties,and peak blast pressure.Using afinite elementfluid-solid coupling algorithm,we performed numerical simulations for a simple case of single-borehole EDC blasting,verifying the effectiveness of the adopted numerical approach.We then performed numerical simulations for dual-borehole EDC blasting with varying in-situ stress conditions and borehole combinations.The results indicate that:(1)rock damage is primarily concentrated on the eccentric side of the borehole due to its smaller decoupling coefficients and the resulting larger peak blast pressure;(2)the formation of through cracks between two boreholes is highly dependent on the relative angleφbetween them,while the extent and direction of the cracks are largely controlled by the application of in-situ stress.This work provides a theoretical basis and reference for optimizing the design of multi-borehole contour blasting in deep rock excavation under significant in-situ stresses,facilitating desired crack propagation while minimizing damage to the surrounding rock.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.42207177)the Natural Science Foundation of Shaanxi Province,China(Grant No.2022JQ-383)the Innovation Capacity Support Plan Project of Shaanxi Province,China(Grant No.2024RS-CXTD-49).
文摘Eccentric decoupled charge(EDC)blasting is a widely used technique for rock fragmentation and tunnel excavation,yet the underlying rock damage mechanisms,particularly in relation to in-situ stresses and multi-borehole combinations,remain underexplored.First,we developed an analytical model for single-borehole EDC blasting,providing insights into the theoretical relationship between the formation of different rock damage zones around the borehole and various influencing factors,including decoupling coefficient,in-situ stress,rock and explosive properties,and peak blast pressure.Using afinite elementfluid-solid coupling algorithm,we performed numerical simulations for a simple case of single-borehole EDC blasting,verifying the effectiveness of the adopted numerical approach.We then performed numerical simulations for dual-borehole EDC blasting with varying in-situ stress conditions and borehole combinations.The results indicate that:(1)rock damage is primarily concentrated on the eccentric side of the borehole due to its smaller decoupling coefficients and the resulting larger peak blast pressure;(2)the formation of through cracks between two boreholes is highly dependent on the relative angleφbetween them,while the extent and direction of the cracks are largely controlled by the application of in-situ stress.This work provides a theoretical basis and reference for optimizing the design of multi-borehole contour blasting in deep rock excavation under significant in-situ stresses,facilitating desired crack propagation while minimizing damage to the surrounding rock.
