Reduction of movement resistance force of pipeline in horizontal curved well at stage of designing underground passage

A method has been developed to reduce the resistance to movement of a pipeline in a horizontal curved well in the construction of underground passages using trenchless technologies. The method can be applied at the design stage. The idea of the proposed method consists in approximating the trajectory of the designed trenchless passage to the equilibrium profile. It has been proved that in order to reduce the resistance to movement of the pipeline arising from contact with the borehole wall, the profile of its initial and final sections must correspond, depending on the initial conditions, to the parabola or hyperbolic cosine equation. Analytical dependences are obtained which allow supplementing the methods of calculation of traction effort in trenchless construction for the case when the profile of the well is given by an arbitrary function. (paper)