Pipe-jacking/micro-tunneling technology in Japan and the development of a new micro-tunnel boring machine (MTBM)

Demand for installation of various pipes/cables in underground is growing due to the rapid urban development in recent years. The common construction methods are open-cut, pipe-jacking, and shield-jacking. It is generally said that shallow pipelines should be constructed by the cut-and-cover method, and deep pipelines might be carried by using a trenchless method. In Japan, when carrying out underground pipeline installation, due to heavy traffic conditions and increasing numbers of underground utilities, the pipe-jacking/micro-tunneling method in urban areas has replaced the conventional cut-and-cover method. This method has been achieved remarkable progress with the development of technical infrastructure. Today’s pipe-jacking/micro-tunneling technology in Japan has been firmly established as a special method for non-disruptive construction of underground pipelines for sewage, water supply, telecommunications, electricity, and gas. As the pipe-jacking /micro-tunneling method has made technological innovations, it becomes available for pipe-line construction of larger diameter, longer drive length with more accuracy by using laser guided targeting, etc. Additionally, the development of effective, appropriately designed utilization of deep ground is also strongly encouraged due to increasingly complex shallow utilities. / This paper discusses the development of pipe-jacking/micro-tunneling technology in Japan, the development of a new micro-tunnel boring machine (MTBM) and its new applications.