The Research On The Mechanism Of The Sonic Drilling Technology

Sonic drilling is a technology that is used widely for drilling and sampling in many developed countries. But there is not this technology in China at present. So it is very basal to research the mechanism of the sonic drilling technology for developing this technology in China. This paper chiefly does some research about the mechanism of the sonic drilling technology by the means of collecting and analyzing the overseas data of sonic drilling, numerical simulation, experimentation and making use of the theories of the machine vibration and the soil and rock mechanics.The paper starts from the analysis of the structure of the sonic vibrator, introduces the machine model of the sonic vibration, suggests the kinematics equations of the sonic drilling by using classic mechanics and analyses the questions of mechanics and power consuming during sonic drilling. Furthermore, the paper advises the choice of frequency during drilling and calculates the rate of sonic drilling. Sonic drilling has three models to break the formations, that are fracturing, shearing and displacing. Explaining the characteristics, application and drilling mechanism by means of the soil and rock mechanics and drilling.It is an obvious characteristic comparing with other drilling methods, sonic drilling can liquefy the saturated sand and other incompact soil to accelerate the drilling. However, the effects of soil liquefaction to the sample must be considered. The paper analyses the soil liquefaction characteristics of sonic drilling, the soil liquefaction modes and the relations between the soil liquefaction and drilling rate.Numerical simulation is a significant way to analyze the tress acted on the soil and rock. The paper establish proper model of impacted soil by the bit to simulate the distortion process, stress on the soil and displacement by using limited analysis, and to inquiry into the bit's cut-in depth in soil layer and the bit's effect on soil sample in terms of bit's structure certain and the percussive work certain. Finally, the in-site trial of sonic drilling machine proved the result of the simulation.