节理化砂岩地层隧道聚能爆破试验研究OA

Based on the Pingshan East Tunnel project in Shenshan Railway,a blasting test was carried out using shaped charge tubes and shaped charge liners,aiming to optimize the blasting outcomes of tunnel excavation and control o-ver excavation and under excavation phenomena.Based on the geological conditions and surrounding rock characteristics of the tunnel,the principle and key process of shaped charge blasting are explained.Through on-site blasting tests,the influ-ences of different peripheral-hole spacings and single-hole charges on blasting outcomes were analyzed,and the economic cost was compared and evaluated.The results show that,in jointed sandstone formations,shaped charge blasting signifi-cantly improves the quality of the face and significantly reduces over excavation and under excavation phenomena by adjus-ting blasting parameters.The volume of over excavation and under excavation has respectively decreased from 35.35 m3 and 0.33 m3 to 4.74 m3 and 0.13 m3,which is significantly reduced compared to traditional blasting methods.Compared with traditional blasting,it can save 15-20 detonators and 8-9 kg of explosives in each cycle of shaped charge blasting,reduce material costs by 401-534 yuan,significantly reduce the number of blasting holes and construction time,and demonstrate high economic and construction efficiency.