微差时间和填塞长度对临近充填体的影响研究

Study on the Influence of Differential Time and Stemming Length on the Adjacent Backfill

嗣后充填采场二步回采过程中,中深孔爆破会对临近充填体产生影响,因此研究充填体爆破响应对保证采矿安全具有重要意义。通过开展现场爆破振动测速,将监测数据进行拟合获得衰减方程,同时采用ANSYS/LSDYNA软件对不同微差时间和填塞长度的方案进行了数值模拟分析。结果表明:①衰减方程推算结果和数值模拟结果基本保持一致,ANSYS/LS-DYNA软件用于模拟爆破对临近充填体稳定性的影响可以获得较为理想的效果。②随着微差时间从19 ms增加到25 ms,矿房与充填体交界面的最大有效应力和峰值速度均呈现先降低后增大的趋势,当微差时间为23 ms时,达到最小值,满足规范要求,对充填体影响最小。③基于矿山原爆破参数方案,设计了4种填塞长度方案,通过分析矿房与邻近充填体交界面的最大有效应力和峰值速度,当填塞长度l_(s1)~ls5分别为2、4、2、5、4 m时,爆破对充填体影响最小,降振效果最佳。研究成果可供类似空场嗣后充填矿山炮孔参数设计参考。

In the two-step stope with subsequent filling,medium-deep hole blasting has an impact on the filling experience,so it is of great significance to study the blasting response of backfill to ensure mining safety.Through the field blasting vibration velocity test,the attenuation equation was obtained by fitting the monitoring data.At the same time,ANSYS/LS-DYNA finite element software was used to conduct numerical simulation analysis on different differential time and different stemming length schemes.The results showed that:①the calculated results of attenuation equation were basically consistent with the numerical simulation results,and ANSYS/LS-DYNA software used to simulate the influence of blasting on the stability of backfill could obtain ideal results.②With the increase of the differential time from 19 ms to 25 ms,the maximum effective stress and peak velocity at the interface between the stope and backfill firstly decrease and then increase.When the differential time is 23 ms,the maximum value reaches the minimum value,which meets the specification requirements and has the least influence on the backfill.③Based on the original mine blasting parameter scheme,four kinds of stemming length schemes were designed.By analyzing the maximum effective stress and peak velocity of the interface between the mine room and the backfill,when the stemming length l_(s1)~l_(s5) was 2,4,2,5,4 m respectively,the blasting had the least influence on the backfill and had the best vibration reduction effect.The study results can be used as a reference for the design of blast hole parameters in similar mines.