Dynamic Analysis Of Pneumatic DTH Hammer Rock Breaking System

With the development of infrastructure construction in China,geotechnical drilling and excavation works are becoming more and more important.As a new way to drill hard rock formations,DTH hammer drilling solves engineering problems that cannot be executed by conventional drilling methods,and it is widely used and studied.Due to the coupling of the movement and the complexity of the formation,the energy utilization of the drill bit is reduced,which affects the efficiency of rock breaking.Therefore,this paper takes pneumatic DTH hammer as the research object and analyzes the dynamics of its rock breaking system to improve the efficiency of rock-breaking in the field.The specific research contents are as follows:Firstly,this paper investigates the current situation of domestic and international research on rock breaking by submersible hammer,clarifies the important components of pneumatic DTH hammer rock breaking system,and establishes the mechanical model of rock breaking system.Secondly,through numerical simulation of the power part of the pneumatic DTH hammer,the energy transfer law of the piston-bit collision process is obtained,and the optimal range of the piston impact velocity is discussed by combining the fatigue strength of each component material.Then,the impact part of the pneumatic DTH hammer is analyzed by dynamics to derive the stress wave transfer of the drill-rock impact process and the rock damage law under the impact action.Finally,since the rock-breaking efficiency is not only related to the impact work,but also the formation lithology and the drilling tooth type are crucial to the rockbreaking efficiency,the influence of each parameter on the fracture efficiency is discussed,and the optimal drilling process under different conditions is explored.The research results show that the influence factors affecting the drilling of pneumatic DTH hammer rock breaking are complex and diverse,and the motion coupling of rock breaking system will affect the rock breaking efficiency to a certain extent.By comparing and analyzing the rock breaking efficiency under different influencing factors,the best process of pneumatic DTH hammer drilling is derived.The research results provide a reference basis for the selection of pneumatic DTH hammer drilling process in different formations and provide some reference and reference for improving the rock breaking efficiency.