损伤条件下深部岩体巷道光面爆破参数研究

Analysis of smooth blasting parameters for tunnels in deep damaged rock mass

岩体条件复杂多变,为了提高光面爆破的适应性、改善光面爆破效果,对损伤条件下深部岩体巷道光面爆破参数进行研究。通过对深部岩体巷道光爆层原岩应力场、光面爆破机制和振动损伤特征进行分析,基于爆炸应力波和爆生气体综合作用理论,考虑高原岩应力和岩石损伤影响,提出了损伤条件下深部岩体巷道光面爆破参数确定的计算方法。研究表明,(1)高原岩应力相当于提高了岩石的抗拉强度,不利于炮孔初始裂纹的形成及贯通,宜减小周边眼间距;(2)岩石损伤后,其他条件不变,光面爆破的炮孔间距和抵抗线值可适当加大;(3)高原岩应力和损伤条件下,光面爆破的炮孔间距较小时,容易造成爆后围岩损伤,降低围岩的稳定性能,因此,提高爆破效果的同时应及时加强支护,以确保施工安全和围岩稳定;(4)本文提出的光面爆破参数计算公式,经现场爆破验证效果良好,适用于复杂多变的岩体环境。

The smooth blasting parameters were researched in deep damaged rock tunnel in order to enhance its adaptability.Based on the theory functioned together by explosion shock wave and explosive gas-pressure,as well as the effect of high static stress and rock damage were also in consideration,parameter calculation formula of smooth blasting under the condition of deep damage rock mass tunnel was proposed through analyzing static stress in burden of perimeter,smooth blasting mechanism and vibration damage characteristics.The result shows that：（1） High rock static stress is equivalent to increasing of rock tensile strength,which make against to formation and transfixion of initial cracks,thus the hole space should be reduced.（2） After the rock was damaged,hole space of smooth blasting and the resistance line value can be appropriately increased while the other conditions are still the same.（3） Under the condition of high rock static stress and damage,surrounding rock with low stability can be easy damaged after smooth blasting when hole space is small.Therefore,the surrounding rock should be reinforced in time to ensure construction safety and rock mass stability as the blasting was improved.（4） The calculation formula of smooth blasting parameters proposed is proved to be valid and adaptable for complex rock environment in on-site blast operation.