基于HJC本构的隔离矿柱爆破崩落排间延时优化及振动控制

Inter-row delay time optimization and vibration control in blasting caving of insulating pillar based on the HJC constitutive model

  • 摘要: 采用爆破崩落法治理采空区时,崩落的矿岩会对采空区下部采场顶板造成冲击扰动, 易引发失稳风险。为保护下部采场顶板稳定性,以白音诺尔1号矿体采空区隐患治理工程为背景,基于矿岩物理力学参数进行HJC本构参数标定;进行SHPB试验探究矿岩动态本构行为,并结合模拟结果验证HJC本构模型可靠性;使用LS-DYNA结合HJC本构参数对隔离矿柱崩落排间延时进行模拟与优化。研究结果表明:在低冲击气压下,2种矿岩的动态压缩应力-应变曲线均呈现滞回效应;在相同冲击气压下,隔离矿柱试件呈现有限的破坏程度,而下部采场顶板矿岩出现更高的破碎程度;在不同排间延时的模拟结果中,100 ms工况下的应力叠加效果显著,隔离矿柱解体程度高,在顶部出现贯通裂缝,失效单元体积达998 m3;爆破后崩落的隔离矿柱在采空区形成有效缓冲层,将露天矿与地下空间隔离,避免了冲击扰动引发的下部采场顶板失稳;巷道爆破振动测点的峰值振速为0.64 cm/s,远小于规定的允许值下限15.0 cm/s。

     

    Abstract: When using the blasting caving method to treat goaf, the collapsing ore and rock can cause shock disturbances to the roof of the lower stope, which may lead to stability risks. This study takes the goaf treatment project of Baiyinnuoer No.1 ore body for analysis to protect the stability of the lower stope roof. Specifically, HJC constitutive parameters were calibrated using the physical and mechanical parameters of the ore and rock; SHPB tests were conducted to investigate the dynamic constitutive behavior of the ore and rock, and the reliability of the HJC constitutive model was verified through simulation results. Using LS-DYNA and HJC constitutive parameters, the inter-row delay time was simulated and optimized for insulating pillar blasting caving. Results show that under low impact air pressure, the dynamic stress-strain curves of both types of ore exhibit hysteresis effects. At identical impact pressure, the insulating pillar specimen shows limited damage, while the ore in the lower stope roof experiences more severe fragmentation. In the simulation under different inter-row delay times, the 100 ms working condition yields significant stress superposition effect, extensive disintegration of the insulating pillar, through-going cracks at the top, and failed unit of 998 m3. The collapsed insulating pillar after blasting forms an effective buffer layer in the goaf, isolating the open-pit mine from the underground space, and preventing the instability of the lower stope roof caused by shock disturbances. The peak particle velocity at the tunnel blasting vibration measurement point was 0.64 cm/s, much lower than the allowable lower limit of 15.0 cm/s.

     

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