Trenchless Tunnelling Technology

A rapidly growing practice, trenchless tunnelling is extremely advantageous for the replacement, rehabilitation or installation of new underground infrastructure with minimal impact to the environment and above-ground structures. 

WSP has a long track record of working with trenchless technologies. Using these techniques, we can assess, rehabilitate, or install underground infrastructure with little to no excavation, thereby minimising the impact on the environment, and reducing the disruption on adjoining buildings, structures, utilities, and the public.



  • Condition assessment of existing pipes and utilities
  • Feasibility, conceptual, and preliminary studies
  • Design, specifications, and contract administration for trenchless projects
  • Design, specifications, and contract administration for pipeline rehabilitation projects


Condition Assessment

To assess the condition of underground infrastructure such as water or sewer networks, we use a range of methods including acoustic leak detection, Closed Circuit Television (CCTV) for visual inspection, and electromagnetic inspection for wall thickness measurement.

We qualify the best for fit method for a specific project by reviewing the data collected from the condition assessment and recommend a plan of action that maximises rehabilitation of the pipeline.


Feasibility and Conceptual Studies

We conduct feasibility studies and provide design and specifications for various trenchless technologies, including:

  • Micro-tunnelling
  • Horizontal Directional Drilling (HDD)
  • Pipe ramming
  • Cured-In-Place-Pipe (CIPP) lining
  • Slip-lining
  • Swage-lining
  • Carbon fibre reinforced polymer
  • Pipe bursting
  • Spray-on liners



Micro-Tunnelling is a trenchless solution used for constructing small diameter tunnels, particularly those under dense traffic roads, railways, or rivers. In comparison to open-trench methods, micro-tunnelling minimises disruptions to the surface during the tunnel construction, and removes the need for personnel to be inside the tunnel during construction operations

This technique installs concrete pipes by a pushing or jacking frame installed in the launching shaft. A Micro Tunnel Boring Machine (MTBM) is attached to the head of the pipe that follows the path of the tunnel as it is being bored. Micro-tunnelling can be used in a range of ground conditions and the cutterhead is customised to the ground conditions at the site.


Horizontal Directional Drilling

Horizontal Directional Drilling (HDD) is a trenchless construction method for installing subsurface piping or conduits by using a surface mounted rig, first to drill a guided hole along a bore path consisting of a shallow arc and then to pull a string of pipe into the hole. 


Trenchless Rehabilitation of Pipelines 

Trenchless technologies for water main and sewer rehabilitation typically includes the installation of a manufactured liner pipe within the host main and/or in-situ spray application of a liner material.

In selecting the preferred method for the rehabilitation, we consider:

  • Pipe material, internal corrosion and tuberculation, joint failure, and external corrosion
  • Operation factors, including hydraulic conveyance limitations and water quality
  • Condition of the pipeline foundation and depth of the pipeline and water table
  • Hydraulic operating pressure and transient pressure requirements
  • Number and type of fittings, including branch and service line connections, valves, fire hydrants, and repair sleeves
  • Duration and level of service interruptions, and the provision of temporary service
  • Site conditions and factors, including local utilities
  • Traffic conditions


The rehabilitation is often done by Cured-In-Place-Pipe (CIPP) lining, slip-lining, swage-lining, or carbon fibre reinforced polymer.