Research On The Response Of Single Teeth Breaking Rock

Increasing drilling speed and reducing costs are two important issues that drilling engineering needs to address.By studying the rock breaking effect and efficiency of single teeth under different loads and different formation conditions,we know that this research is helpful to guide the optimization of the bit structure and optimization of drilling parameters.At home and abroad,the effects of loading load,formation conditions and single-tooth structure parameters on the rock-breaking effect have been studied comprehensively.At present,the existing theory has a deep understanding of the crack generation and propagation mechanism under the action of single teeth and the geometry and kinematics of the drill bit,but the study about the relationship of the rock breaking effect and drilling pressure,rotational speed and rock mechanics needs to be strengthened.So this paper has carried out the following research:(1)The influencing factors of sirtgle-tooth rock breaking are investigated comprehensively.Rock breaking method,rock breaking tool and rock breaking model are investigated comprehensively.The research status of the single tooth breaking rock and the key factors affecting the single tooth breaking rock are summarized.The research content and technical route of this paper are determined.(2)A single-tooth indentation model is established.The single-tooth intrusion experiment is carried out by using the electronic universal testing machine.The typical curve of the force-displacement under the single-tooth intrusion is obtained.The rock breaking index is quantitatively evaluated and the rock elastic modulus and hardness is calculated.The shape and size of the fracture pit is measured.The measured parameters can be the basis for numerical simulation.(3)According to the single-tooth intrusion experiment,the Abaqus software was used to establish a numerical simulation model of single-tooth broken rock.Considering the different cohesion and internal friction angle rocks under different loads,the fracture pits with different width,depth and volume are obtained.According to the statistical data of different cohesion,internal friction angle,load and width,depth and volume of the fracture pit,the quantitative relational expression between them is established by non-dimensional method.This relational expression is solved.According to the results of numerical simulation,the force required for the single-tooth crushing process is analyzed.The influences of cohesion,internal friction angle and depth to the force are analyzed.All of the analysis is helpful to have a correcting understanding of the single-tooth breaking rock with different cohesion and internal friction angle.All of the analysis laid the foundation for measuring the effect to break rock with different load.(4)A single-tooth rock-breaking experiment is performed to verify the relationship between the width,depth,volume of the fracture pit and cohesion,intermal friction angle,load.The single-tooth rock breaking experimental device is debugged and the taken rock samples is processed into regular shapes.Using the rock breaking experimental device,the rock samples of the Ziliujing,Wujiaping and Jinbaoshi were crushed at different pressures and speeds.The drilling rate and experimental crushing volume are obtained under the experimental conditions.The drilling speed expression is established according to the relationship between the experimental volume and the theoretical volume.The known parameters are substituted into the drilling speed expression to calculate the theoretical calculation drilling speed,and the experimental drilling speed is compared with the theoretical calculation drilling speed to verify the establishment of the relationship.In summary,the relationship between rock breaking effect and drilling pressure,rotational speed and rock properties is analyzed.The established relationship can be used to calculate the drilling speed when the different rocks are broken with diflFerent loads and different speeds in the project.This relational expression has certain guiding significance for measuring the rock breaking effect.