GEO-Instruments have worked extensively on many major tunnelling projects where precise monitoring and early warnings of movement on surrounding structures is vital.

One of the biggest concerns when tunnelling works are undertaken is the potential for settlement to occur, not only at surface level but also below ground. Both have the potential to impact on structures and third party assets.

Monitoring activities during tunnelling

When tunnelling in urban areas the ground response in the surrounding area can be very difficult to predict. Therefore most construction projects implement mitigation measures to protect assets from such settlement occurring. One such method of mitigation is Compensation Grouting, whereby the ground is pre-treated prior to any works and then again during the works as a reactive process.

The use of monitoring on sites is essential to successful implantation of mitigation measures as well as monitoring structural health, firstly by establishing baseline results before any works take place, and then by monitoring the on-going works as the works advance. Following the completion of construction works the monitoring remains in place to measure post works movements which are likely to occur due to the reactive nature of different soils.

Underground works

GEO-Instruments have a considerable amount of experience working within different underground environments, each of which has their own specific requirements. Environments we have worked in before include sewers, tunnels, access shafts and underground rail lines, both live and isolated. Tunnel monitoring usually involves night working with teams of confined space trained workers, and well established method statements to manage the works effectively which often come with time and space constrained working conditions.

Implementation of cutting edge technologies

Tunnelling and underground monitoring works, by their nature, introduce potential problems with cable routing and data signal which would otherwise impact on the ability to provide consistent and reliable measurements. GEO-Instruments uses innovative wireless technologies from industry recognised suppliers at the forefront of the market to minimise cable runs, while implementing redundancy communication systems to provide a continuous flow of data from the site.