Research On Mechanical Properties And Packing Effect Of Cuttings With Different Particle Sizes

In view of the problems such as blasting energy leakage,unsatisfactory rock fragmentation and punching caused by poor filling during blasting excavation,In this paper,the granular filler(rock debris)commonly used in engineering blasting is taken as the research object.Through theoretical analysis,dynamic triaxial test,numerical simulation and field test,the influence of filling particle size and length on blasting effect is deeply explored.Based on the mechanism of blasting rock breaking,the role of shock wave,stress wave and explosion gas in each stage of blasting rock breaking process is analyzed in depth.Based on the mechanism of blasting rock breaking,the change process of filling under blasting load and the influence of filling on blasting effect are analyzed in detail.The dynamic triaxial tests were carried out on the with different particle sizes of granular filling(rock debris)to obtain the dynamic shear modulus – dynamic strain curve,damping ratio – dynamic strain curve,and the maximum dynamic elastic modulus and maximum dynamic shear modulus under different confining pressures.Through the analysis of the experimental data,research findings that the influence of particle size on the blockage performance of granular filler is greater in shallow hole blasting.And the influence gradually decreases with the increase of borehole depth.The particle size of granular backfill(rock debris)is in the range of 0 – 3 mm.The larger the particle size is,the better the shear performance under blasting load is.Application of ANSYS / LS-DYNA finite element numerical simulation software and field test,the analysis and study of liquid(water)and different particle sizes of granular(cuttings)filling holes show that the plugging effect of liquid(water)on holes is far less than that of granular filling materials.The particle size of granular filler(rock debris)is in the range of 0 – 10 mm.The larger the particle size is,the better the plugging performance is and the higher the energy utilization rate of explosive is.The movement process of the filling material in the blasting process is decomposed,and the influence of the filling length on the blasting effect and the factors affecting the optimal filling length are theoretically discussed through the force analysis.Combined with ANSYS /LS-DYNA finite element numerical simulation software,the rock throwing velocity was extracted by calculating the volume of blasting funnel,and the optimal filling length was obtained by fitting the relationship curve.Reasonable filling length can not only reduce the harm caused by flying rock,but also make the blasting effect reach the ideal state.This paper studies the applicability and selection basis of granular(rock debris)particles for hole filling.Based on the above research results,it is of great significance to improve the hole filling theory and solve the problem of water hole blasting punching.