Wastewater Disposal Pipeline installed by Microtunneling in Rome

For wastewater disposal, the municipality of Rome designed a sewer bypass in Farnesina, which runs between two already established concrete DN 3500 collectors. Totaling a length of 320 m, the line was planned with a nominal diameter of 1400 mm. Disruptions through works on site were to be kept to a minimum, so that the densely populated area would be able to keep up its busy flow, especially during sports events when thousands of visitors gather in the area. The trenchless solution microtunneling was chosen for installation. Apart from being non-disruptive it also kept the construction site comparably small.The first stretch of 135 m was excavated with the thrust from the main station, whereas the longest stretch of 185 m had to be driven with an intermediate jacking station.HOBAS CC-GRP Jacking Pipes DN 1400 with an external diameter 1,499 mm and a weight of 415 kg per meter were utilized for this project and allowed thrust forces up to 3476 kN. Thanks to the products’ smooth outer surface and comparably small wall thickness, it was possible to reduce the amount of slurry as well as excavation material. In fact, it limited the use of bentonite based lubricant to the final sections of both drives and sped up the installation rate considerably. Also the standard pipe length of 6 m and the light weight of HOBAS products proved to be highly advantageous, for these contributed to reducing installation cost while once again shortening installation times.