Trenchless techniques

Trenchless techniques is a collective noun for the installation of an underground infrastructure whereby the soil surface is disturbed as little as possible. This technique is used where there is little space for example, and/or hinder due to shipping and road traffic. Trenchless techniques can also be used in order to limit any issues with the existing infrastructure. VLTT conducts many projects at home and abroad, both onshore and offshore where special techniques need to be applied.

The general technology

We have machines which can carry out horizontal underground drilling, after which conduits, cables or pipelines can be pushed or dragged through the excavated space. Using the open front technique, we can drill diameters from 20 centimetres up to one and a half metres. Other techniques allow us to drill diameters up to three metres. The closed front technique is used when drilling below the groundwater level.

Open Front Drilling technique (OFT)

The main feature of this technique is the open fronted pipe

Closed Front Drilling (CFT)

This technique can be used “in wet works”

Horizontal Directional Drilling (HDD)

This technique is executed from above ground level.


Technique developed by VLTT. Combines HDD and Microtunneling


Technique developed by VLTT and applied during HDD


This method is particularly suitable for projects in urban areas

Subsea Drilling®

This is the underwater drilling rig developed by VLTT

Trenchless removal of Cables and Pipelines

The name says it all!


At VLTT, engineering goes much further than simply designing the ideal drilling line


VLTT undertakes drilling projects not only on land, but also at sea. We drill trenches for cables to offshore wind parks, for example. There is increasing demand for wind turbines and the exchange of green energy, and the number of large projects undertaken by VLTT is growing accordingly. We recently connected wind parks to the shore using a specially developed drilling technique. For these projects, VLTT developed the Pipe Pusher in-house, which is the size of a sea container. If the right tool does not exist, we simply manufacture it ourselves!