The development of a shield machine requiring no reception shaft: A pipejacking method enabling shield withdrawl and retrieval at the starting shaft

This paper describes a pipe-roof construction method, known as an auxiliary method to temporarily prevent ground from collapsing during underground construction. A shield machine developed for this technique, problems encountered, and experimental and project records are also detailed. The pipe-roof construction method uses a pipejacking method performed by a tunnelling machine. Thrust data analysis, experiments on the inside diameter of steel pipes, and experiments on the cutting of shear pin were performed to determine the inside diameter of the steel pipes in order to develop a retrievable shield machine. The results of the construction project indicated areas for further development. 13 figs., 3 tabs.