Research On Rock Breaking Performance Of Drilling System For Drilling Jumbo

Drilling jumbo is the key equipment of drilling and blasting method of tunnel, water-power engineering and mining currently, and drilling system is working mechanism of drilling jumbo, hasing an important influence on the high efficiency and reliability of rock breaking. Drilling system is subjected to serious bit wear, low work efficiency during the production. Carring out research on influence of drilling system working parameters on impact crushing performance to improve adaptability, high efficiency and reliability of drilling jumbo. In this paper, the theoretical analysis, experiment and simulation are combined to investigate the rock breaking preformance of drilling system.Based on working process and characteristics of drilling jumbo drilling system, regarding the national standard of rock drilling machines and gas dynamic tool performance testing methods as a guide, the impact fragmentation experimental equipment is designed for the purpose of convenient test operation and data measurement, which mainly consists of six parts: mechanical system, hydraulic system, electrical system, water supply system, gas supply system and test system.Based on the Boussinesq problem, the rock stress state and fragmentation mechanism under the impact action of blade type tool and ball type tool is researched. Based on AUTODYN, the simulation of crack extension and failure model of rock breaking under the impact action of blade type tool and ball type tool is carried out.Research on hard rock and medium strength rock impact fragmentation is carried out on the impact fragmentation experimental equipment, and some researches, which mainly include determination of impact energy, rock breaking performance of drilling system without factors interaction, rock breaking performance of drilling system with factors interaction and drilling system working performance regression, are designed to study working parameters(impact power, rotational speed, feed pressure and bit type) influence on rock breaking performance, the primary and secondary order of working parameters influencing drilling velocity, working parameters interaction influence on rock breaking performance, the optimal working parameters and the regression relationship between drilling speed and working parameters, which can provide a basis for drilling system selection, working parameters determination, the optimization of impact device and the estimate of project progress.The 3D simulation model of piston-bit-rock is established by using LS-DYNA dynamic simulation software, and drilling system working parameters are expanded to of impact energy, impact frequency, rotational speed, feed pressure and bit type, and orthogonal test method is applied to simulation arrangements, which can explore rock crushing process under different bits and working parameters influence on drilling speed. The simulation results are in agreement with the experimental results, which indicates that the simulation model is correct.The sealing device of impacting and rotating is designed, so it can allow high pressure water jet to pass through drill rod under axial and rotational movement, and high pressure water jet can be applied to the existing drilling system and the volume of it increases slightly. It can be explored the drilling effect assisted with high pressure water jet though the combination of water jet and impact in order to improve drilling speed of drilling system, and improve the reliability and service life of drilling jumbo.