Tunnelling & Conveyance

Tunnelling to connect new and existing water receptors

Population growth and dense cities along with an increased focus on environmental and ecological issues have necessitated more efficient water and wastewater systems.  Tunnels are increasingly being seen as the most cost-effective, non-obtrusive and ecologically compliant method to connect new and existing water sources.  Recently our team utilised trenchless tunnelling techniques on a major project with minimal impact and disturbance to the sensitive urban site which included Dublin city's busiest motorway and a public park.  Water supply tunnels, aqueducts, intake and outfalls, interceptors, trunk and drainage pipelines are key components of water conveyance systems.  They transfer water and wastewater from collection points to treatment facilities/plants and then transport them for distribution or disposal.  Our water team have designed all components of water conveyance systems such as pumping stations, flow control facilities, stormwater collection, stormwater tunnels and storage tanks. Across challenging ground conditions, Ayesa develops and manages the construction of water and wastewater tunnels, aqueducts, CSO (Combined Sewer Overflow) tunnels and offshore outfalls and deep shafts.   
Our tunnelling design team expertise in numerous tunnelling methodologies, used in a range of significant infrastructure projects:

• Bored tunnels in hard rock or soft ground
• CSO Tunnels
• Deep Shafts
• Micro-tunnelling, pipejacking and directional drilling
• Offshore Outfalls
• Sequential Excavation Method (SEM)
• Trenchless methods
• Tunnel boring machines (TBM)
• Tunnelling in gassy or contaminated ground sites
• Wastewater Tunnels, Water Supply Tunnels and Aqueducts

A Holistic View of Water

Our experts consider water issues throughout the entire lifecycle, giving us a holistic view that allows us to create more efficient and effective designs.  We detect challenges early on to optimise usage, reduce project costs, and provide communities with long-term sustainable solutions.  When engineering water conveyance tunnels, our multidisciplinary experts consider geotechnical investigations, ground improvement, groundwater hydrology, hydraulics of flows, transient pressures and other construction and operational requirements.

Today, our clients include national utilities such as Irish Water, which we are helping to upgrade the existing sewer network in Blanchardstown in an 88 million euros project. Our team designed the 30m deep underground storage tanks (with a total capacity of approximately 30,000m³) and the associated pipeline which runs close to the M50 motorway for approximately three kilometres. The pipeline is being installed using trenchless tunnelling techniques due to its minimal impact and disturbance when compared to open-cut methods.