Study On The Motion Law Of Underwater Blasting Blocks Based On Fluent-EDEM Coupling

The blasting block and its movement form produced by underwater drilling and blasting have always been the key to the safety of surrounding hydraulic facilities and the efficiency of slag removal after blasting.This paper takes underwater bench blasting,underwater rock plug blasting and deep-water Cofferdam Demolition Blasting as the main research line,the underwater motion process of blasting block is numerically simulated by Using Fluent-EDEM fluid structure coupling technology.And based on theoretical analysis,model experiment and numerical simulation,the motion law of underwater blasting block is simulated and studied.The following work has been accomplished:The underwater bench model blasting experiment of small equivalent explosive was carried out,and the cement materials in the blasting area are replaced by discrete cement mortar block particles.Fluent-EDEM coupling technology was used to simulate the experiment,and the significant influence of charge weight amount on the operation form of block particles is clarified.With the increase of charge weight,the larger the disturbance of the block particle group in the blasting area,the greater the maximum displacement of block particles in the vertical and horizontal directions.The numerical simulation results show that,the blasting load mainly plays the role of blasting loosening under the charge weight of 0.6g,and the throwing and flying movement of block particles is more obvious under the charge weight of 0.8g.The underwater rock plug model blasting experiment with small equivalent explosive was carried out,and the rock plug area is replaced by discrete block particles.The experimental results show that,The height of water head and the opening angle of rock plug have an influence on the penetration effect,with the increase of water head height,the penetration effect of rock plug blasting is better,and the increase of opening angle is more conducive to the collapse of block particles.Fluent-EDEM coupling technology was used to simulate the experiment,combined with the model test results,the penetration mechanism of underwater rock plug blasting is clarified: under the action of blasting load,a blasting funnel is formed at the far water end of the rock plug,and the near water end of the rock plug plays the role of blasting loosening;finally,under the action of water scouring and self weight,the block particles near the water end flow into the slag pit to complete the penetration process of rock plug blasting.The Fluent-EDEM coupling method based on DPM coupling interface was used to simulate the blasting demolition process of the third phase RRC cofferdam of the Three Gorges Project.The simulation results show that,the blasting demolition and dumping process of deep-water cofferdam can be divided into three stages according to the motion state: first,after the completion of blasting,the upper weir body rotates around the fulcrum,and the weir crest completes the water inflow process;the second is the sliding movement of the upper weir body along the slope of the lower reserved part;finally,the upper weir body falls freely until it touches the ground.