分段空场嗣后充填法扇形孔爆破数值模拟与参数优化OA

To address the issues of backfill damage and stope boundary irregularities caused by fan-shaped bore-hole blasting in sublevel open stoping with subsequent backfilling,this study focuses on the underground stope of Xinqiao Phosphate Mine as a case study.Numerical models were developed using LS-DYNA finite element software to comprehensively analyze the blasting performance of fan-shaped medium-deep holes under various operational con-ditions.Field-measured blasting contours of the stope were compared with numerical simulation results to evaluate the influence of different loading application methods on the blasting damage prediction accuracy.The simulations em-ployed both experimentally recorded borehole wall pressure time-histories and a constitutive explosive material model coupled with the JWL equation,revealing that the measured load time-histories yielded more precise blasting effect representations.Building upon this foundation,the study systematically simulated fan-shaped blasting under one-step mining,two-step mining,and special stope conditions by examining two key variables:inter-sidewall distance and ini-tiation delay time.Subsequent analysis focused on surrounding rock mass damage distribution patterns and blasting-induced vibration characteristics.Results indicate that in one-step mining scenarios,inter-sidewall distance exhibits limited impact on surrounding rock mass stability,while initiation delay time emerges as the predominant factor gov-erning blast fragmentation efficiency.At a 0.3 m inter-sidewall distance,blasting damage primarily concentrated within the ore caving zone,achieving effective bulk fragmentation while substantially mitigating surrounding rock damage risks.In two-step mining scenarios,backfill stability demonstrates high sensitivity to toe burden distance,with damage risks markedly damage decreasing when exceeding 0.6 m.While sequential hole initiation enhanced frag-mentation,it exacerbated backfill damage.Special stope conditions required asymmetric sidewall parameter design and optimized borehole arrangement to minimize backfill impacts.These findings culminate in an optimized fan-shaped blasting parameter system tailored for Xinqiao Phosphate Mine's A-orebody,delivering both theoretical frame-works and practical methodologies for backfill mining blasting operations.