EXPERIMENTAL RESEARCH OF THE DYNAMICS OF TRENCHLESS RECONSTRUCTION OF THE DISTRIBUTION PIPELINES WITH"T-type TRACTION PISTON" TECHNOLOGY

Abstract

The article describes the technology of the trenchless reconstruction of distribution pipelines using the "T-type Traction Piston" technology. The essence of this technology is drawing a new polyethylene pipeline into a worn steel one using a piston. The piston moves under the pressure of air supplied into behind-the-piston space by the compressor. The annular space in the boring (operating) trench is sealed with a sealing system. The authors have designed and constructed the experimental stand to determine the resistance forces which act on the movable system during the reconstruction of the distribution pipelines using the “T-type Traction Piston” technology. Its schematic diagram is presented. Using experimental methods the authors have determined the effort which is required to draw one linear metre of a polyethylene pipeline into a worn steel pipeline, the friction force of the piston cups on the walls of the worn steel pipeline and the friction force of the polyethylene pipe in the cups of the sealing system. The authors have ascertained the sum of experimentally determined resistance forces which act on a movable system while drawing a new polyethylene pipeline into a worn steel one by the piston. The authors have designed and constructed the experimental installation (unit) to study the dynamics of drawing a new polyethylene pipeline into a worn steel one by a piston. The experimental studies have been carried out for various tilts of a worn steel pipeline as to the horizon, various air rates, various external diameters of polyethylene pipes. The authors have experimentally determined the regularities of the air pressure change at the pipeline startover time during the movement of the piston inside a steel pipe and while drawing the polyethylene pipe within the worn steel one by a piston. The dependence of the drawing velocity on the air-flow rate and on the length of the drawn section has been studied. The experimental tests have proved that "T-type Traction Piston" technology can be used for the reconstruction of the distribution pipelines.