Study On Operating Stability Of Pressure-bearing Drilling Rod For Upward Raise Boring Machine

The upward raise boring machine is the drilling equipment which is based on mechanical rock breaking and the drilling direction from bottom to top.In the process of drilling,there is a large gap between the shaft well and the drilling rod.The drilling rod bears pressure in axial direction,gravity and torsion.It is easy to lose stability.It is necessary to study the operating stability of the pressure-bearing drilling rod.According to the theory of elastic mechanics and material mechanics,the force analysis of upward raise boring machine was carried out.The theoretical deduction of the critical force formula about the drilling rod stability is carried out by using the energy method.The numerical simulation of drilling rod is carried out by ANSYS finite element software.The specific research contents and the results obtained are as follows:The stability of the drilling rod is improved by adding stable drilling rod after analyzing the process of pilot drilling.During the process of reaming drilling and the process of drilling without pilot,the distance between the drilling rod and well wall is larger than drilling rod's diameter.In order to ensure the drill rod's stability,some stabilizers are added on drill rods.After simplifying and analyzing the restraint of the drill rods,the expression formula of drill's critical force formula(including the gravity)is deduced by the energy method.In order to find out the reasonable arrangement position of the stabilizer under different drilling pressure,the data are put into the formula.According to the critical force formula of the drilling rod,the factors influencing the stability of the drill pipe are found out,and the influence degree of each factor is also given.Through the finite element analysis software ANSYS,the drilling rod model is established,and the modal analysis of the non-stabilizer drill pipe is carried out.According to the deformation regular in different positions of the drilling rod,the position of the stabilizer is determined.And the result is compared with the theoretical arrangement position.The application of critical force formula deduced by energy method is contributed to upward raise boring machine working successfully at diamond mine construction site.And the result is good.As a result,a method about drill pipe's stability is obtained,while avoiding increasing of deflection rate at the same time.It is a reasonable way to add stabilizers onto drilling rods for pipe's stability.It also provides theoretical basis for the future research on the stability of drilling rod.