时滞型岩爆的切缝法防治机制研究

Mechanism study of slot prevention of delayed rockburst

针对西南地区水电工程中岩爆频发的问题,提出在洞周向围岩内部切缝的方法防治时滞型岩爆。从理论分析、数值模拟和施工工艺3方面探讨了切缝法防治时滞型岩爆机制与方法。切缝为环向应变提供变形空间,降低了围岩表面的环向应力大小。切缝底部及切缝间形成的塑性区,消耗了围岩中的部分弹性应变能。理论分析和数值模拟的结果表明,合理布局切缝的部位、间距及数量可以提高防治的效果,在实际操作中还应根据围岩的特性合理选择和设计切缝的成型方案,如采用破碎孔和聚能预裂爆破等方法,以准确控制切缝尺寸。

The slot-cut method is put forward,aiming at the problem of frequent rockburst for hydropower projects in Southwest China.The mechanism and method of slot-cut prevention of delayed rockburst are discussed by theoretical analysis,numerical simulation,and construction technology.The existence of slots provides extra space for circumferential deformation,thus decreases the circumferential stress on the surface of surrounding rock mass.The plastic strain formed on the slot bottom and between slots absorbs part of the elastic strain energy stored in the rock mass.It＇s revealed by the numerical analysis that the location,spacing and number of slots should be arranged reasonably for better prevention effect.In actual practice,the slots-cutting operation should be well designed,for more accurate control on the dimensions of slots,and can be accomplished by drill-blasting or accumulative explosives pre-split blasting.