Development of joining method of polyethylene branch pipe for gas and non-excavation construction method

摘要

The purpose of this study is joining main and branch gas pipes by friction welding without digging a paved road. By this development, only making a hole al the vertical side of the paved road, the branch pipe can be connected to the main pipe. In this study, an end face of branch pipe was welded to a side of the main pipe. Furthermore, considering that the gas main pipe is laid in the ground, the influence of mud on the joining state is examined. The experimental results are as follows.a. Branch pipe welding without digging a paved road was enabled by the friction welding method.b. The developed method docs not require digging and repairing the paved road. Therefore, construction cost can be reduced, and traffic is not obstructed.c. Tensile strength and elongation of branch pipe friction welded joint were 17.7-17.8 MPa and 520-525%, respectively. These were nearly equal to those of base polyethylene.d. A large amount of mud was eliminated from the faying surface by friction. Therefore, the influence of mud on tensile strength and elongation was not recognized.