Abstract

The possibility of drilling enlarged-bottom hole depends on the working parameters such as the rotational speed of the main axle @, and the penetration speed of ground blade 2 as well as the structural parameters: the pile diameter of the bottom enlarged D, the height of the bottom enlarged, h and the enlarged-bottom angie, α In this paper, a mathematical model for the working parameter of enlarged-bottom drilling equipment was proposed, establishing the relationship between the working parameter and the soil properties. This model gives a method to calculate exactly the relations between the working parameter, the structural parameters and the soil properties. A group of the boundary conditions, such as overloading and limit values of α, 1, 2 are defined. And the causes for the overload of a machine are determined. It is concluded that the enlarged bottom angle value of drilling hole is governed by the resistance of the soil and the relationship between the pile diameter and the torque of the drilling base machine is found to be an exponential