【摘要】 为减小爆破对隧道围岩的损伤,在传统光面爆破装药结构基础上,设计一种在炮孔一侧安放PVC-U材料来保护隧道围岩的装药结构,并分析了该方法的作用机制。为分析和验证PVC-U管对隧道围岩损伤的防护效果,利用Φ100mm的霍普金森试验装置进行隧道围岩损伤防护试验,从试件宏观破坏、应力波衰减和能量变化3方面进行了分析。结果表明:防护材料改变了岩石的受力状态,当防护材料厚度从0增加到6.24mm时,无防护材料的试件的破坏程度比有防护材料的试件严重,且随着防护材料厚度的增加破坏程度不断减小;试件的应力峰值呈不断降低趋势;应力峰值的降低率不断增加;耗散能与入射能比值从61.08%下降到39.97%。可见,防护材料对岩石冲击损伤具有一定防护作用。该方法在某巷道掘进中得到应用,并取得了良好效果。更多还原

【Abstract】 In order to decrease the blasting damage to tunnel surrounding rocks,a new charging structure and its mechanism are proposed based on the traditional smooth blasting charging structure. The PVC-U material is placed beside the burn-cut cavities to protect the surrounding rocks of the tunnel. The Φ100 mm Hopkinson test equipment is used for the purpose of researching the weakening level of the PVC-U pipe. The analysis is made on macroscopic damage of the test sample,attenuation of stress wave and dissipation of energy respectively. The test results show that: the stress state of rock is changed by the protective layer and the damage of the rock without protective layer is worse than that with the protective layer;and as increasing of the thickness of protective layer from 0 to 6.24 mm,the degree of rock damage decreases;the stress peak shows decreasing trend;and the reduction rate of peak stress value increases instantly. The ratio of dissipation of energy and the incident is reduced from 61.08% to 39.97%. Thus the conclusion can be drawn that the impact damage of rock is protected by the protective layer. Good results have been obtained in a roadway excavation project.更多还原