中深孔爆破动载荷下块石充填体强度响应研究

Study on Intensity Response of Rubble Backfill to Dynamic Loading of Medium-Length Hole Blasting

为分析地下中深孔爆破动力载荷作用对充填体安全稳定性的影响和论证废石注浆构筑人工矿柱技术可行性,结合卡房分矿试验采场工程实际,在物理力学试验的基础上,利用LS-DYNA软件对充填体在连续微差爆破动力载荷下的强度响应进行了数值模拟试验。研究结果表明:预裂缝对爆破载荷作用具有明显的减弱效果,且减弱效果随预裂缝的长度增加而递增,当预裂缝长度为爆破落矿宽度2倍时,振动峰值降低83.07%,最大拉应力降低91.14%,能够满足充填体强度要求。在预裂缝存在的情况下,振动主频降低,衰减周期增长,需要更大的微差时间对振动主相进行分离,但是随微差时间进一步增加,降振效果趋缓。数值模拟结果分析表明,选用合理的爆破参数可以对块石充填体人工矿柱进行中深孔爆破。

In order to analyze the impact of dynamic loading caused by underground medium-length hole blasting on filling body′s security and stability,as well as testify the technical feasibility of constructing artificial pillar by waste-rock grouting,numerical simulation test was conducted for intensity response of backfilling body to dynamic loading caused by millisecond sequential blasting with LS-DYNA Software,based on the physical mechanics test.Results showed that pre-splitting crack could effectively reduce an impact of blasting dynamic loading,and such effect would increase progressively with the increasing of length of pre-splitting crack.When the length of pre-splitting crack was twice the width of ore break by blasting,the vibration peak decreased by 83.07% and the maximum tensile stress reduced by 91.14%,which met the required backfill strength.With the existence of pre-splitting crack,the main vibration frequency reduced and the decay period prolonged.It required more millisecond delay time to separate the main phase of vibration.But with an increase in millisecond delay time,vibration reduction effect was slowing down.Results from numerical analysis show that the medium-length hole blasting can be done in the artificial pillar made of rubble backfill with reasonable blasting parameters.