Trenchless installation of a new 400 metre sewer system

Trenchless sewer installed under railway and river Sile in Italy

Contractor LF Costruzioni has laid a 400m trenchless sewer system beneath an active railway line and the river Sile in the city of Treviso, in northeast Italy.

Trenchless installation of a new 400 metre sewer system

Background In the historic city of Treviso, the construction of a new sewer system was required to support urban infrastructure in a highly sensitive environment. The project alignment runs beneath both a railway line and the river Sile, in an area characterised by high groundwater levels similar to Venice. The project brought together several demanding load cases, creating exceptionally complex design and construction conditions. The Challenge The project combined an unusual concentration of demanding design and construction requirements: ● Installation beneath an active railway line ● Crossing below the Sile river ● High groundwater levels ● Installation depth of approximately 11 m ● Sensitive urban environment in the city centre ● Long-term resistance to hydraulic and geotechnical loading This combination of conditions created a highly complex project environment, requiring a pipe system capable of performing reliably under multiple simultaneous load cases. Project Overview Country: Italy City: Treviso Year of construction: 2025 Application: New Sewer Total length: 400 m Nominal diameter: DN 800 Technology: KERA.Drive Installation: Trenchless Consultant: ENKI Contractor: LF Costruzioni Client: ATS, water company The Solution A microtunnelling approach using a slurry system was selected to enable safe and precise installation under this exceptional combination of conditions. The new sewer was constructed using DN 800 KERA.Drive vitrified clay jacking pipes, supplied by Steinzueg-Keramo, providing a direct jacked solution without the need for additional casing pipes. Steinzueg-Keramo’s KERA.Drive vitrified clay pipes were selected due to their: ● High structural capacity for jacking applications ● Excellent resistance to corrosion and aggressive environments ● Proven watertightness under high external pressure ● Long service life with minimal maintenance requirements The ability to install a single-pipe solution under such demanding conditions significantly simplified the overall system while maintaining long-term performance. Installation details Given the groundwater conditions and sensitive surface structures, a slurry-supported microtunnelling method was employed to ensure controlled excavation and continuous face support. ● Installation method: Microtunnelling (slurry system) ● Nominal diameter: DN 800 ● Total length: approx. 400 m ● Installation depth: approx. 11m Results ● Safe installation beneath railway and river without surface disruption ● Successful construction at 11m depth under high groundwater pressure ● No requirement for additional casing pipe ● Durable, corrosion-resistant sewer system ● Long-term operational reliability with minimal maintenance ● Successful delivery under a combination of highly demanding project condition Conclusion The Treviso project demonstrates how multiple complex load cases and boundary conditions can be successfully managed within a single infrastructure scheme. KERA.Drive vitrified clay jacking pipes provided the structural capacity, durability and watertightness required for a direct jacked solution. Despite the exceptional combination of loading conditions, the pipes remained well within their performance limits, delivering a robust and future-proof sewer system for generations to come. Lorenzo Vidus Rosin, Sales Engineer Italy at Steinzueg-Keramo, says: “KERA.Drive is the sustainable solution. Not only from the material perspective, but also from an installation point of view.” For more information about Steinzueg-Keramo, visit: www.steinzeug-keramo.com Or contact: uk.steinzeug-keramo@wienerberger.com Ends Notes to editor Steinzeug-Keramo is a wienerberger company, one of the leading providers of innovative, ecological solutions for the entire building envelope, in the fields of new build and renovation, as well as infrastructure in water and energy management, with over 200 production sites in 28 countries. With 170+ years of experience, Steinzeug-Keramo is not just a supplier, but a systems provider with specialised expertise in the manufacturing, installation and operation of wastewater systems. To learn more about wienerberger, visit: https://www.wienerberger.com/en.html